Restaurant Receipts Cards - Highland Park ISD
Restaurant Receipts Cards - Highland Park ISD
Restaurant Receipts Cards - Highland Park ISD
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<strong>Restaurant</strong> <strong>Receipts</strong> <strong>Cards</strong><br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
The following four cards serve as a group that can be used collectively to answer the question.<br />
Alice’s Diner sells only four items, which<br />
have individual prices of $2, $3, $4, or $5.<br />
Alice’s Diner sells only four items, which<br />
have individual prices of $2, $3, $4, or $5.<br />
Qty<br />
2<br />
3<br />
CUSTOMER RECEIPT<br />
Item<br />
Super Sodas<br />
Big Burgers<br />
Qty<br />
5<br />
6<br />
CUSTOMER RECEIPT<br />
Item<br />
Super Sodas<br />
Big Burgers<br />
TOTAL:<br />
$18<br />
TOTAL:<br />
$39<br />
THANK YOU!!<br />
THANK YOU!!<br />
After dining there, Group A got this receipt.<br />
What is the cost of each individual item?<br />
After dining there, Group C got this receipt.<br />
What is the cost of each individual item?<br />
Alice’s Diner sells only four items, which<br />
have individual prices of $2, $3, $4, or $5.<br />
Alice’s Diner sells only four items, which<br />
have individual prices of $2, $3, $4, or $5.<br />
CUSTOMER RECEIPT<br />
CUSTOMER RECEIPT<br />
Qty<br />
2<br />
Item<br />
Big Burgers<br />
Qty<br />
2<br />
Item<br />
Monster Nachos<br />
2<br />
Fast Fries<br />
3<br />
Big Burgers<br />
2<br />
Super Sodas<br />
2<br />
Fast Fries<br />
4<br />
Super Sodas<br />
TOTAL:<br />
$18<br />
TOTAL:<br />
$38<br />
THANK YOU!!<br />
THANK YOU!!<br />
After dining there, Group B got this receipt.<br />
What is the cost of each individual item?<br />
After dining there, Group D got this receipt.<br />
What is the cost of each individual item?<br />
©2010, TESCCC 08/01/10 page 9 of 60
<strong>Restaurant</strong> <strong>Receipts</strong><br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
Fill in or complete the information on this page as you work through the problem.<br />
<br />
What information is found on each receipt?<br />
Receipt A<br />
Receipt C<br />
Receipt B<br />
Receipt D<br />
<br />
What prices are possible for each item?<br />
List possible item prices<br />
Check—Do the prices work?<br />
<br />
What prices can be eliminated for certain items?<br />
Write the names of the items<br />
in the first column.<br />
Write the possible costs for each item in the top row.<br />
Eliminate<br />
possibilities by<br />
placing X’s in the<br />
appropriate boxes.<br />
©2010, TESCCC 08/01/10 page 11 of 60
Systems of Equations<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
Using B for the cost of a burger, F for the cost of fries, N for the cost of nachos, and S for the cost of a<br />
soda, write equations for each statement below.<br />
2 sodas and 3 burgers cost $18.<br />
5 sodas and 6 burgers cost $39.<br />
2 burgers, 2 fries, and 2 sodas cost $18.<br />
2 nachos, 3 burgers, 2 fries, and 4 sodas cost $38.<br />
DEFINITION:<br />
DEFINITION:<br />
When used together, these form a ________________________ of equations,<br />
which is a set of two or more equations with two or more unknowns (or variables).<br />
The ________________________ to a system lists the values that can be used<br />
for each variable to make the equations in the system true (or, “check”).<br />
Samples:<br />
1)<br />
2x<br />
3y<br />
4z<br />
3<br />
x z 4<br />
x 2y<br />
3z<br />
4<br />
This is a _______ _____________ of equations because it uses<br />
_____ _________________ and has _____ ________________.<br />
Which of the following would be the solution to this system?<br />
A) x 4,<br />
y 1,<br />
z 2 B) x 9.5,<br />
y 0, z 5. 5<br />
C) x 5,<br />
y 3,<br />
z 1<br />
2)<br />
2x<br />
7y<br />
y <br />
1 x 2<br />
9<br />
3<br />
This is a _______ _____________ of equations because it uses<br />
_____ _________________ and has _____ ________________.<br />
Which ordered pair shows the solution to this system?<br />
A) (15, 3) B) (8, 1) C) (2, -2)<br />
Below, circle the correct solution to each equation. How can you determine the solution?<br />
3)<br />
4) 5x<br />
3y<br />
2z<br />
16<br />
y 3x<br />
8<br />
x y 5 z<br />
x 4y<br />
1<br />
8x<br />
5y<br />
3z<br />
25<br />
A) x 3,<br />
y 1<br />
A) (1, -0.2, 5.8)<br />
B) x 7,<br />
y 29<br />
B) (-2, 4, 7)<br />
C) x 7,<br />
y 9<br />
C) (1, 1, 4)<br />
These answers are<br />
called “ordered triples”<br />
©2010, TESCCC 08/01/10 page 13 of 60
Plug into the System<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
Evaluate each equation for the given values in the ordered triple. If the values “check” in the equation,<br />
then shade in the corresponding box. When all items are complete, the remaining boxes (which have<br />
not been shaded) will spell out a quote. Be sure to check each solution set for each equation. The<br />
equation will have more than one set that works.<br />
1) System of Equations: (-2, 3, -3) (2, 6, -4) (3, 4, -9) (1, 5, 1)<br />
3x 2y<br />
z 14<br />
IFT HER HEY EAS<br />
2x y 5z<br />
22<br />
ONT ONY GIV EYO<br />
4x 3y<br />
2z<br />
18<br />
URU LIN GER LED<br />
Which ordered triple is the solution to the system? __________<br />
2) System of Equations: (3,9,-2) (-3, 4, 5) (1, 5, -4) (5, 1, 1)<br />
2x y 4z<br />
23<br />
SYS PAPE TEMP RWR<br />
9x 4z<br />
7<br />
ITET HERL UTNA HEO<br />
x 6y<br />
4z<br />
15<br />
THE RWAY THY OUSE<br />
Which ordered triple is the solution to the system? __________<br />
Place the remaining letters (from left to right) in the blanks.<br />
____________ ____________ ____________ ____________ ____________ ____________<br />
____________ ____________ ____________ ____________ .<br />
—Juan Ramon Jimenez<br />
©2010, TESCCC 08/01/10 page 15 of 60
Graphing 22 Systems (pp. 1 of 4)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
Getting Started<br />
Consider the system:<br />
y 2x<br />
3<br />
y<br />
<br />
1 2<br />
x<br />
2<br />
For each equation, make a table of<br />
ordered pairs (x,y). Then graph each line.<br />
Which ordered pair appears in both<br />
tables?<br />
y 2x<br />
3<br />
x y<br />
0<br />
1<br />
2<br />
3<br />
4<br />
y<br />
<br />
x<br />
0<br />
1<br />
2<br />
3<br />
4<br />
1 2<br />
x<br />
y<br />
2<br />
What do we call this point, in terms of the system?<br />
What do we call this point in terms of the graph?<br />
_______________________<br />
_______________________<br />
IMPORTANT:<br />
When the equations in a system can be ___________________,<br />
then the ___________________ to the system can be described<br />
using the _____________________ of the _________________ of _____________________.<br />
<br />
Why?<br />
Use the slope and intercept of each linear equation to generate the graphs. Then state the solution to<br />
the system.<br />
3<br />
2<br />
y <br />
2<br />
x 2<br />
y x7<br />
3<br />
1) System:<br />
2) System:<br />
y 3x<br />
1<br />
y x3<br />
Solution:<br />
Solution:<br />
©2010, TESCCC 08/01/10 page 20 of 60
Graphing 22 Systems (pp. 2 of 4)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
Continue graphing to find the solution to each system.<br />
3) System:<br />
y<br />
y<br />
<br />
<br />
3<br />
4<br />
x <br />
5 7 2<br />
x<br />
4) System:<br />
y<br />
y<br />
<br />
<br />
1<br />
2<br />
3<br />
2<br />
x 1<br />
x 5<br />
Solution:<br />
Solution:<br />
5) System:<br />
y<br />
y<br />
5<br />
<br />
1 x 3<br />
3<br />
6) System:<br />
y<br />
y<br />
2x<br />
1<br />
3 2x<br />
Solution:<br />
Solution:<br />
©2010, TESCCC 08/01/10 page 21 of 60
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
Graphing 22 Systems (pp. 3 of 4)<br />
Systems of equations can also be solved using the CALC 5: intersect command on a graphing<br />
calculator. However, before equations can be entered, you must solve each equation for “y”.<br />
Sample<br />
System Equations in “Y=” form Sketch the Graph Table Check Solution<br />
x 2y<br />
3x<br />
4y<br />
9<br />
8<br />
Y 1 = 0.5x + 4.5<br />
Y 2 = (-3/4)x + 2<br />
x Y1 Y2<br />
-4 2.5 5<br />
-3 3 4.25<br />
-2 3.5 3.5<br />
-1 4 2.75<br />
0 4.5 2<br />
(-2, 3.5)<br />
7) System Equations in “Y=” form Sketch the Graph Table Check Solution<br />
2x<br />
y<br />
4x<br />
y<br />
5<br />
12<br />
Y 1 =<br />
Y 2 =<br />
x Y1 Y2<br />
8) System Equations in “Y=” form Sketch the Graph Table Check Solution<br />
4x<br />
7y<br />
14<br />
8y<br />
8 5x<br />
Y 1 =<br />
Y 2 =<br />
x Y1 Y2<br />
9) System Equations in “Y=” form Sketch the Graph Table Check Solution<br />
3x<br />
5y<br />
30<br />
6x<br />
20 10y<br />
Y 1 =<br />
Y 2 =<br />
x Y1 Y2<br />
10) System Equations in “Y=” form Sketch the Graph Table Check Solution<br />
3xy<br />
5<br />
10 6x<br />
2y<br />
Y 1 =<br />
Y 2 =<br />
x Y1 Y2<br />
©2010, TESCCC 08/01/10 page 22 of 60
Graphing 22 Systems (pp. 4 of 4)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
When solving systems<br />
(such as by graphing),<br />
three different cases<br />
can occur.<br />
What type of lines?<br />
The lines are… The lines… The lines…<br />
What type of system?<br />
What type of solutions?<br />
______ solutions<br />
______ solution<br />
(represented by the<br />
An _______________<br />
of solutions (or, every<br />
Other Vocabulary<br />
Sometimes, the<br />
“__________ ______”<br />
is used to describe the<br />
solution to such a<br />
system.<br />
Symbol:<br />
______________.)<br />
If the two equations in<br />
the system graph into<br />
lines which intersect at<br />
a single point, then they<br />
are called<br />
_________________<br />
equations<br />
________ on the line)<br />
If the two equations in<br />
the system have the<br />
same graph, then they<br />
are called<br />
_________________<br />
equations<br />
On graph paper or on a calculator, solve each system graphically. Then describe:<br />
The type of lines—parallel, intersecting, or coincident (coinciding).<br />
The type of system—inconsistent, consistent independent, or consistent dependent.<br />
The type of solutions—one solution, no solutions, or infinitely many solutions.<br />
11)<br />
y<br />
y<br />
2x<br />
4<br />
<br />
1 x 3<br />
1<br />
12)<br />
y<br />
y<br />
<br />
3<br />
2<br />
x 1<br />
3x<br />
7<br />
13)<br />
y<br />
y<br />
<br />
<br />
2<br />
5<br />
2<br />
3<br />
x 1<br />
x 3<br />
14)<br />
y 3x<br />
5<br />
12x<br />
4y<br />
20<br />
15)<br />
4x<br />
2y<br />
10<br />
6x<br />
3y<br />
12<br />
16)<br />
y 0.8x<br />
2<br />
5x<br />
4y<br />
8<br />
©2010, TESCCC 08/01/10 page 23 of 60
Systems by Algebraic Methods (pp. 1 of 4)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
The “substitution” method can be used to solve systems of equations algebraically.<br />
x y 11<br />
7x 4y<br />
22<br />
This is the system.<br />
Solve for a variable in one of the equations.<br />
In the other equation, replace this variable<br />
with its equivalent expression.<br />
Solve (for the numerical value of the<br />
variable).<br />
Substitute this answer into another equation<br />
to find the value of the other variable.<br />
• Where would you start?<br />
For each system, without solving, identify which variable in which equation it would be easiest to<br />
solve for first. Explain why this variable is easiest to solve for.<br />
4x<br />
y 3<br />
7x<br />
2y<br />
4<br />
9x<br />
11y<br />
32<br />
7y<br />
x 20<br />
8x<br />
y 90<br />
3x<br />
7y<br />
112<br />
3x<br />
9y<br />
51<br />
2x<br />
4y<br />
18<br />
Now solve the systems. Show your work.<br />
1) 4x y 3 7x 2y<br />
4<br />
2) 9x 11y<br />
32 7y<br />
x 20<br />
3) 8x y 90 3x 7y<br />
112 4) 3x 9y<br />
51 2x<br />
4y<br />
18<br />
©2010, TESCCC 08/01/10 page 32 of 60
Systems by Algebraic Methods (pp. 2 of 4))<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
Sometimes, solving systems with the substitution method can yield strange results…<br />
Try to solve these systems.<br />
5) 5x y 2 10x 2y<br />
9<br />
6) 3x 9y<br />
24<br />
2x<br />
6y<br />
16<br />
When solving a system algebraically…<br />
If you end up with an equation that is ______________ true,<br />
4 9<br />
the system has _____________________ (or, it is _________________________ )<br />
or, graphically, the equations’ lines would be ___________________________.<br />
If you end up with an equation that is _________________ true,<br />
-24 = -24<br />
the system has _____________________ (or, it is _________________________ )<br />
or, graphically, the equations’ lines would be ___________________________.<br />
Continue solving these systems algebraically using the substitution method.<br />
7) 3x y 155<br />
6x 7y<br />
5 8) 7x 2y<br />
3<br />
2x<br />
4y<br />
42<br />
9) 2x 12y<br />
40<br />
x 6y<br />
19 10) 9x y 6 3x<br />
5y<br />
42<br />
©2010, TESCCC 08/01/10 page 33 of 60
Part B<br />
Systems by Algebraic Methods (pp. 3 of 4)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
The “elimination or combination” methods can also be used to solve systems of equations.<br />
When given a system of equations, you can create other important equations by…<br />
2x<br />
5y<br />
4x<br />
3y<br />
19<br />
24<br />
12x<br />
30y<br />
____<br />
12x<br />
9y<br />
____<br />
24x<br />
39y<br />
____<br />
_________ 42<br />
y = 2<br />
For each equation select a<br />
constant to multiply by that<br />
will make the absolute value<br />
of the coefficient of one of the<br />
variables equal.<br />
Multiply both sides of each<br />
equation by the selected<br />
constants.<br />
(Multiplication of equal value<br />
on both sides of an equation)<br />
Combine the equations together by addition<br />
or subtraction. Which eliminates one variable?<br />
(Addition or subtraction of equal values on<br />
both sides of an equation)<br />
In some cases, combining the equations (or, adding them together) eliminates a variable.<br />
This allows you to solve the system. Try a few on your own.<br />
2x<br />
y 11<br />
a b 19<br />
5x<br />
3y<br />
31<br />
9x<br />
2y<br />
Ex.<br />
11)<br />
12)<br />
13)<br />
x y 7<br />
a b 7<br />
5x<br />
2y<br />
4<br />
x 2y<br />
17<br />
7<br />
3x = 18<br />
x = 6<br />
2(6) + y = 11<br />
y = -1<br />
• Solution: (6, -1)<br />
Other times, to eliminate a variable through combination, one equation must first be multiplied by a<br />
constant. Use this method on the systems below.<br />
2x<br />
5y<br />
19 ( <br />
2)<br />
4x<br />
10y<br />
38<br />
3x<br />
2y<br />
23 <br />
( <br />
4)<br />
__________=____<br />
Ex.<br />
14)<br />
4x<br />
3y<br />
24<br />
4x<br />
3y<br />
24<br />
2x 8y<br />
62<br />
2x<br />
8y<br />
62<br />
2x<br />
5(2) 19<br />
2x<br />
10 19<br />
2x<br />
9<br />
x 4.5<br />
Solution: (4.5, 2)<br />
7y<br />
14<br />
y 2<br />
15)<br />
3x<br />
2y<br />
x 5y<br />
4<br />
62<br />
16)<br />
3x<br />
2y<br />
4x<br />
8y<br />
10<br />
8<br />
©2010, TESCCC 08/01/10 page 34 of 60
Systems by Algebraic Methods (pp. 4 of 4)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
Finally, you can multiply BOTH equations by a constant, so that when they are combined, a variable<br />
will be eliminated. Then solve the system.<br />
Ex.<br />
8x<br />
3y<br />
41<br />
( 5)<br />
<br />
_____________ = 205<br />
6x<br />
5y<br />
39 ( )<br />
<br />
_____________ = -117<br />
_____________ = 88<br />
_______ + _______ = _____ _________ = ______<br />
Solution: (4, 3)<br />
MULTIPLY <br />
the equations by constants so<br />
that something will “cancel”<br />
ADD (or COMBINE) <br />
the equations together<br />
SOLVE <br />
the resulting equation<br />
PLUG <br />
the value back into an original<br />
equation to find the other<br />
variable<br />
17)<br />
4x<br />
5y<br />
3x<br />
2y<br />
70<br />
18<br />
18)<br />
12x<br />
7y<br />
8x<br />
11y<br />
59<br />
39<br />
19)<br />
10x<br />
7y<br />
15x<br />
8y<br />
16<br />
29<br />
20)<br />
6x<br />
7y<br />
2x<br />
5y<br />
47<br />
21<br />
©2010, TESCCC 08/01/10 page 35 of 60
Puzzling Systems (pp. 1 of 2)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
On a separate piece of paper, solve each system using graphing, substitution, or combination.<br />
Record the point of intersection, and match it to the letters to complete the coded punch line.<br />
y 2x98<br />
D<br />
y x99<br />
( _____, _____ )<br />
y x6<br />
N<br />
x 3y<br />
( _____, _____ )<br />
x 3y<br />
E<br />
x2y<br />
5<br />
( _____, _____ )<br />
x y 6<br />
R<br />
3x<br />
y 4<br />
( _____, _____ )<br />
L<br />
y x 2<br />
y <br />
1 x 2<br />
4<br />
( _____, _____ )<br />
y x 10<br />
S<br />
y 2x<br />
( _____, _____ )<br />
2x<br />
3y<br />
11<br />
U<br />
x 3y<br />
7<br />
( _____, _____ )<br />
y x<br />
4<br />
I<br />
x 2y<br />
( _____, _____ )<br />
8x<br />
4y<br />
28<br />
P<br />
y 2x<br />
7<br />
( _____, _____ )<br />
y 3x<br />
14<br />
H<br />
2y<br />
4x<br />
8<br />
( _____, _____ )<br />
x y 6<br />
O<br />
x 3y<br />
2<br />
( _____, _____ )<br />
y x 1<br />
A<br />
y 2x<br />
2<br />
( _____, _____ )<br />
(1, 100) (-8, -4) (-9, -3) (8, 2) (-10, -20) (3, 4) (-4, -1) (1, 7)<br />
(2, 8) (3, 1) (4, 2) Infinitely<br />
many<br />
solutions<br />
(3, 1) (1, 7)<br />
©2010, TESCCC 08/01/10 page 47 of 60
Puzzling Systems (pp. 2 of 2)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
On a separate piece of paper, solve each system using graphing, substitution, or combination.<br />
Record the point of intersection, and match it to the letters to complete the coded punch line.<br />
y 3x<br />
3<br />
H<br />
6x<br />
3y<br />
6<br />
( _____, _____ )<br />
11x<br />
2y<br />
1<br />
C<br />
9x<br />
3y<br />
24<br />
( _____, _____ )<br />
Don’t argue with a dummy!<br />
People watching may not<br />
be able _____.<br />
2x<br />
2 2y<br />
L<br />
2x<br />
y 2<br />
( ____, _____ )<br />
4x<br />
8y<br />
16<br />
O<br />
3x<br />
4y<br />
2<br />
( _____, ____ )<br />
D<br />
y 2x<br />
6<br />
y <br />
1 x 2<br />
( _____, _____ )<br />
4<br />
3x<br />
y 3<br />
R<br />
6x<br />
3y<br />
3<br />
( _____, ____ )<br />
y x<br />
12<br />
E<br />
y x 4<br />
( _____, _____ )<br />
3<br />
y x<br />
2<br />
T<br />
y 2x<br />
7<br />
( _____, ____ )<br />
x y 6<br />
F<br />
x y 10<br />
( _____, _____ )<br />
4x<br />
6y<br />
3<br />
N<br />
2x<br />
3y<br />
10<br />
( _____, ____ )<br />
2x<br />
6y<br />
26<br />
I<br />
y x 3<br />
( _____, _____ )<br />
(-2, -3) (2, 1) (-2, -3) (8, 4) (-3, 4) (-3,4) (-2, -3) (1, 0) (8, 4)<br />
(4, 2) (1, 4) (8, 2) (8, 2) (8, 4) (4, 9) (8, 4) No Sol. (1, -5) (8, 4)<br />
©2010, TESCCC 08/01/10 page 48 of 60
Systems Situations (pp. 1 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
For each situation, define variables and set up a system of equations. If you have trouble at first, try<br />
one of these strategies to help: 1) List possibilities, 2) Trial and error, 3) Grouping like numbers.<br />
1. Copies. A teacher has to make 159 copies of a review packet for the students in her classes.<br />
When she arrives in the workroom, she starts using both copy machines (call them X and Y).<br />
During the copying, machine X runs out of paper, so it only printed half as many packets as<br />
copier Y. How many copies does each machine print?<br />
Variables:<br />
x = Number of copies made by Machine X<br />
System:<br />
y = Number of copies made by Machine Y<br />
2. Fast Food. A bunch of friends went to the Snack Shack for lunch. The first family ordered 4<br />
hamburgers and 4 orders of fries for $9.00. The next family ordered only 1 hamburger and 2<br />
orders of fries for $3. How much would each item cost individually?<br />
Variables:<br />
System:<br />
= 4h + 4f = 9<br />
= h + 2f = 3<br />
3. Exercise. Several times a week, Chuck goes to the gym to run and swim. When running, Chuck<br />
burns 35 calories per minute, and when he swims he burns 30 calories per minute. He has<br />
found a way to burn 730 calories after exercising for a total of 23 minutes. How long does Chuck<br />
spend at each activity?<br />
Variables:<br />
=<br />
System:<br />
=<br />
4. Coins. Donald has a bunch of nickels and dimes in his piggy bank. If there are 100 coins in the<br />
bank that make a total of $6.60 in change, how many of each type of coin does Donald have?<br />
Variables:<br />
=<br />
System:<br />
=<br />
©2010, TESCCC 08/01/10 page 52 of 60
Systems Situations (pp. 2 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
5. Golf. To play golf at Blackhawk Range, golfers must first pay a $75 membership fee, and must<br />
still pay $7 for every round of golf. At the Royal Estates Country Club Course, golfers only have<br />
to pay $5 per round, but their membership dues are $185. After how many rounds of golf would<br />
the total amount paid by a golfer be the same at both golf courses?<br />
Variables:<br />
=<br />
System:<br />
=<br />
6. Discs. There are 43 discs in Josh’s entertainment center. However, some of them are music<br />
CD’s and some of them are video DVD’s. If the number of music CD’s in Josh’s collection is 5<br />
less than three times the number of DVD’s, how many of each type does he own?<br />
Variables:<br />
=<br />
System:<br />
=<br />
7. Salesman. Carmen sells cars at a dealership that pays her a monthly salary of $2500 plus a<br />
commission of $125 for every car she sells. A competing dealership has offered her a job that<br />
pays a greater monthly salary of $2700, but only gives $100 commission on each car sold. How<br />
many cars would Carmen have to sell in a month to get the same pay from either dealership?<br />
Variables:<br />
=<br />
System:<br />
=<br />
8. Circus. There are 18 performers in Barnum’s Famous Flea Circus. However, none of them are<br />
actually fleas—they are either spiders (with 8 legs) or bugs (with 6 legs). Mr. Barnum wants to<br />
provide every performer with tiny new shoes for the ends of each of their many legs. If this<br />
requires a total of 130 shoes, how many spiders and bugs are in the circus?<br />
Variables:<br />
=<br />
System:<br />
=<br />
©2010, TESCCC 08/01/10 page 53 of 60
Systems Situations (pp. 3 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
9. Amused. Several families are in line to enter an amusement park. The first family pays $54 for<br />
two adult tickets and two child tickets. The second family pays $105 for 3 adults and 5 children.<br />
What are the ticket prices for adults and for children?<br />
Variables:<br />
=<br />
System:<br />
=<br />
10. Age. Samantha has an older brother. Right now, he is twice her age. But 8 years ago, her<br />
brother was 3 times her age. How old is each person now?<br />
Variables:<br />
=<br />
System:<br />
=<br />
11. Health. Sherri is considering joining a health club. To be a member of Roman’s Gym, she would<br />
have to pay a sign-up fee of $49.99 and then $25 per month. Another club, Athens Fitness<br />
Center, charges less per month (only $18) but has a $126.99 sign-up fee. After how many<br />
months of membership would the total paid to each club be the same?<br />
Variables:<br />
=<br />
System:<br />
=<br />
12. More Discs. After cleaning house, Josh took a box of 29 used discs to sell at the flea market.<br />
Some were computer games (which he sold for $2 each), some were music CD’s (which he sold<br />
for $3 each), and the rest were video DVD’s (which he sold for $4 each). If Josh sold everything<br />
(which included twice as many DVD’s as computer games), and he made a total of $93, how<br />
many of each type of disc did he sell?<br />
Variables:<br />
=<br />
System:<br />
=<br />
=<br />
©2010, TESCCC 08/01/10 page 54 of 60
Situation Problems Involving Systems<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 01<br />
1. The band booster club is selling coffee and hot chocolate at the soccer games. Both drinks are<br />
sold in the same paper cup. They sold $272.25 worth of hot drinks and used a total of 275<br />
cups at the last game. If hot chocolate sells for $1.25 and coffee sells for $.75, how many of<br />
each type of hot drinks did they sell?<br />
2. Susie is going to purchase a new freezer. One brand costs $1800 and estimates $60 per<br />
month to operate. A more expensive brand costs $2600, but only costs $40 per month to<br />
operate.<br />
a. Write an equation representing the cost of each freezer in terms of months owned.<br />
b. Find the total cost of each after 1 year, 2 years, and 3 years.<br />
c. Plot the graph of each on the same axes.<br />
d. Find the break-even point for the two freezers. When does this occur? What is this<br />
cost?<br />
e. If Susie plans on keeping this freezer for five years, which freezer would be the most<br />
economical? Explain.<br />
3. Treebolt High School is running an inventory of graphing calculators. They have two types, TI-<br />
83 + and TI-83 + Silver Edition. Records show they purchased 350 calculators for a total of<br />
$37,750. If TI-83 + costs $95 and TI-83 + Silver Edition costs $125, how many of each type of<br />
calculator should the school have in inventory?<br />
4. One brand of car with a regular engine costs $21,500 to purchase, and 32 cents per mile to<br />
operate. The same car with a fuel-injection engine costs $22,500 to purchase and only 29<br />
cents per mile to operate.<br />
a. Write an equation for each particular car comparing total cost in terms of miles<br />
operated.<br />
b. Calculate the cost of operating each vehicle for 1,000, 10,000, and 50,000 miles.<br />
c. Plot the graph of each on the same axes.<br />
d. Find the break-even point for the two vehicles. At what mileage does this occur? What<br />
is this cost?<br />
e. If Trey switches cars after 40,000 miles, which car would be the most economical?<br />
Explain.<br />
©2010, TESCCC 08/01/10 page 44 of 60
Solving Systems with Technology and Matrices (pp. 1 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
How can we solve problems requiring more variables and more equations using technology? First,<br />
you must make sure that the system is in “standard form.” This means that the variable terms are<br />
lined up on the left side of the equations, and the constants are on the right.<br />
Sample System:<br />
x 2y<br />
z 9 Looks good <br />
2x<br />
y 3z<br />
Add 3z to both sides <br />
3x<br />
1 4y<br />
5z<br />
Add 1, -4y, and -5z to both sides <br />
Standard Form:<br />
x 2y<br />
z 9<br />
2x<br />
y 3z<br />
0<br />
3x<br />
4y<br />
5z<br />
1<br />
Using Inverse Matrices<br />
With this method, think of the system as…<br />
33 matrix<br />
of<br />
coefficients<br />
<br />
31<br />
matrix of<br />
variables<br />
=<br />
31<br />
matrix of<br />
constants<br />
In this case:<br />
1<br />
<br />
<br />
2<br />
<br />
3<br />
2 1 x<br />
9<br />
1 3<br />
<br />
<br />
<br />
<br />
<br />
<br />
y<br />
<br />
0<br />
<br />
4 5<br />
<br />
z<br />
<br />
1<br />
Enter the coefficients in one matrix (here, [A]):<br />
Using Augmented Matrices<br />
With this method, think of the system as an<br />
augmented 34 matrix.<br />
1<br />
2 1 9<br />
<br />
<br />
<br />
2 1 3 0<br />
<br />
<br />
3 4 5 1<br />
The first three<br />
columns are<br />
coefficients<br />
The<br />
variables<br />
are not<br />
shown<br />
The last<br />
column<br />
holds the<br />
constants<br />
Enter this augmented matrix into the calculator:<br />
Enter the constants in another (here, [C]):<br />
Compute the solutions using [A] -1 [C]:<br />
From the MATRIX<br />
find the command:<br />
MATH menu, scroll down to<br />
rref(<br />
This places a matrix in “reduced row echelon”<br />
form.<br />
So, the solutions are:<br />
x<br />
<br />
<br />
y<br />
<br />
<br />
z<br />
2 <br />
<br />
<br />
<br />
5<br />
<br />
<br />
3<br />
Here, solutions appear in the last column.<br />
So, the solutions are:<br />
x<br />
2 <br />
<br />
<br />
y<br />
<br />
<br />
<br />
5<br />
<br />
<br />
z<br />
<br />
3<br />
©2010, TESCCC 08/01/10 page 14 of 40
Special Cases<br />
Solving Systems with Technology and Matrices (pp. 2 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
Inverse Matrices<br />
Augmented Matrices<br />
1<br />
0 0 5 <br />
Infinite number of<br />
Infinite number of<br />
<br />
<br />
ERR: SINGULAR MAT<br />
0 1 0 2<br />
solutions<br />
solutions<br />
<br />
<br />
<br />
0 0 0 0 <br />
1<br />
0 0 5 <br />
<br />
<br />
No solutions ERR: SINGULAR MAT No solutions<br />
0 1 0 2<br />
<br />
<br />
<br />
0 0 0 1 <br />
Since the inverse matrices do not distinguish between infinite and no solutions, another method must<br />
be used to determine which one is the correct answer.<br />
Examples:<br />
1.<br />
x 2y<br />
2z<br />
7<br />
4z<br />
3x<br />
1<br />
y z 6<br />
Using Inverse Matrices<br />
Using Augmented Matrices<br />
Standard<br />
form<br />
Standard<br />
form<br />
Written as<br />
Matrix<br />
Equation<br />
Written as<br />
Augmented<br />
Matrix<br />
Matrix<br />
Solution<br />
Matrix<br />
Solution<br />
Values of<br />
x,y,z<br />
Values of<br />
x,y,z<br />
©2010, TESCCC 08/01/10 page 15 of 40
Solving Systems with Technology and Matrices (pp. 3 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
2.<br />
x 2y<br />
2z<br />
7<br />
4z<br />
3y<br />
1<br />
x 6 z<br />
Using Inverse Matrices<br />
Using Augmented Matrices<br />
Standard<br />
form<br />
Standard<br />
form<br />
Written as<br />
Matrix<br />
Equation<br />
Written as<br />
Augmented<br />
Matrix<br />
Matrix<br />
Solution<br />
Matrix<br />
Solution<br />
Values of<br />
x,y,z<br />
Values of<br />
x,y,z<br />
©2010, TESCCC 08/01/10 page 16 of 40
Learning About Lingos<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
Solve each system.<br />
Find the code letter for<br />
the answers and fill in<br />
the blanks below to<br />
answer the questions.<br />
A B C D E F G H<br />
2,1,3 3,1, 12<br />
1 <br />
1, , 1<br />
3<br />
<br />
<br />
6,6,6 1, 2, 2 5,7, 1<br />
1, 6, 6 1, 2,3 <br />
I L M N O P R S W<br />
1 <br />
1 1 1 <br />
1 1 <br />
1, 1, 6 1, ,1<br />
3<br />
1,3, 2 ,0,6<br />
<br />
2<br />
, ,2<br />
23<br />
7,2,0 6,6,3<br />
, ,1<br />
<br />
23<br />
6, 2,5 <br />
<br />
1)<br />
2xy 3z<br />
1<br />
3xy 2z<br />
4<br />
x2y z<br />
5<br />
2)<br />
3x4y z<br />
1<br />
x3y z<br />
2<br />
2xy 2z<br />
1<br />
3)<br />
4x 5y z<br />
8<br />
4x3y 2z<br />
10<br />
2xy z<br />
5<br />
4)<br />
3x3y z<br />
3<br />
2x3y 2z<br />
3<br />
x6y 3z<br />
0<br />
5)<br />
4xy 62z<br />
3x 2y 53z<br />
x y z<br />
1<br />
6)<br />
2x z13y<br />
2x 2z 6y<br />
5x4y 3z<br />
6<br />
7)<br />
2x 6y z<br />
5<br />
x y z10<br />
x 8y 2z<br />
0<br />
8)<br />
2xy 3z<br />
19<br />
3x2y 3z<br />
19<br />
x4y 2z<br />
9<br />
9)<br />
4x 6y 3z<br />
2x5z 3y<br />
5<br />
9y 4z 6x4<br />
10)<br />
2x 7 y 4z<br />
2x y 2z<br />
x 3z 222y<br />
11)<br />
2x y z<br />
12<br />
3xy 4z<br />
36<br />
xy z<br />
18<br />
Did you know that more than …<br />
8 million people speak _____ _____ _____ _____ _____ _____?<br />
9 8 3 11 6 8<br />
14 million people speak _____ _____ _____ _____ _____ _____ _____?<br />
9 7 2 6 8 4 8<br />
5 million people speak _____ _____ _____ _____ _____ _____ _____?<br />
10 4 5 1 8 9 6<br />
©2010, TESCCC 08/01/10 page 18 of 40
Mixing It Up (pp. 1 of 5)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
WARM UP<br />
Compute answers to each of the following “mixture” problems.<br />
A) Florence took a road trip to the beach, which was several hundred<br />
miles away. As she left, she had to drive 36 mph through the city<br />
for about half an hour. Once she hit the highway, she drove 68<br />
mph for 3.5 hours. Then, as she approached the beach, the traffic<br />
was so heavy she could only go 20 mph for the last 30 minutes.<br />
<br />
<br />
<br />
How many hours was Florence on the road?<br />
How many miles did Florence travel?<br />
Over the course of her trip, what was Florence’s average speed?<br />
B) When you buy hydrogen peroxide, it is really a solution diluted<br />
with water. One bottle comes in a 2% solution, and another<br />
comes in 5% strength. Suppose you mix 40 ml of the 2% solution<br />
with 80 ml of the 5% solution.<br />
<br />
How many milliliters of the mixture is actually pure hydrogen<br />
peroxide?<br />
<br />
What percent of this mixture is hydrogen peroxide?<br />
C) Donna always gets really high grades on tests and quizzes (95’s<br />
every time), but she only does homework half the time (so her<br />
homework grade is a 50).<br />
<br />
Donna’s teacher has a policy where tests and quizzes make<br />
up only 30% of students’ grades and homework makes up<br />
the other 70%. Under this system, what would Donna’s class<br />
grade be?<br />
<br />
A teacher down the hall uses a different policy, where tests and quizzes are 60% of the<br />
grade, and homework is only 40%. What would Donna’s grade be if she had this teacher?<br />
©2010, TESCCC 08/01/10 page 24 of 40
Mixing It Up (pp. 2 of 5)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
For each situation, define variables and set up a system of equations that relates them. Then, solve<br />
the system using matrices.<br />
1) When traveling to see relatives, Duke drives part of the trip on the highway at 60 mph and the<br />
rest through cities at 40 mph. The 270-mile trip takes him a total of 5 hours. How much of this<br />
time does he spend on the highway? How much time through cities?<br />
Solutions:<br />
=<br />
System:<br />
=<br />
Matrix Equation:<br />
2) On the return trip, Duke encounters some road construction that slows him down. While he is<br />
still able to go 60 mph on the highway and 40 mph through cities, he can only go 20 mph past<br />
the construction. He spends twice the time passing the construction as he does on the highway,<br />
so this time the 270-mile trip takes 7.8 hours. How much of this time does he spend on the<br />
highway, in the city, and through road construction?<br />
Solutions:<br />
=<br />
=<br />
System:<br />
=<br />
Matrix Equation:<br />
©2010, TESCCC 08/01/10 page 25 of 40
Mixing It Up (pp. 3 of 5)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
Continue setting up and solving systems for these situations.<br />
3) In the school’s chemistry lab, a certain acid is stored in two different dilutions. One bottle<br />
contains a weaker solution that is only 25% acid, but another has a stronger solution of 65%<br />
acid. Students must pour some from each container to make 60 ml of a solution that is 50%<br />
acid. How much from each container should be used?<br />
Solutions:<br />
=<br />
System:<br />
=<br />
Matrix Equation:<br />
4) When Ebenezer won a $250,000 lottery jackpot, everyone started asking for donations.<br />
His brother Bob said, His sister Sally said, And his friend Fred said,<br />
“I need a loan! I can pay<br />
you back in a year. I’ll<br />
even pay you back with<br />
4% interest!”<br />
“I need $20,000 more than Bob<br />
does, but I want to start my own<br />
business. And you’ll earn more<br />
than 4% on this sweet deal.”<br />
“No way. You need to put<br />
your money in the stock<br />
market. It’s doing great right<br />
now.”<br />
Ebenezer split all his money among these three investments. Bob repaid his loan and interest,<br />
and the investment in Sally’s business came back with 7% profit. Even though the money he<br />
put in the stock market lost 8.2%, Ebenezer still came out with an extra $5,830.<br />
How much money did he place into each of these investments?<br />
Solutions:<br />
=<br />
=<br />
System:<br />
=<br />
Matrix Equation:<br />
©2010, TESCCC 08/01/10 page 26 of 40
Mixing It Up (pp. 4 of 5)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
Continue setting up and solving systems for these situations.<br />
5) When extreme athletes compete at a motorcycle jumping competition, judges give them scores<br />
on a scale of 0-10 in three categories: use of fundamentals, degree of difficulty, and overall<br />
style. However, these categories are not weighted equally in determining the final score.<br />
Funda- Difficulty<br />
score<br />
Final<br />
Style<br />
mentals<br />
D. Howser 7.4 8.2 8.8 8.01<br />
R. Finn 7.4 7.8 9.6 8.23<br />
J. Hoban 8.0 7.6 8.6 8.15<br />
=<br />
=<br />
The table shows how the category<br />
scores for three riders determined their<br />
final rating.<br />
By what percent is each category<br />
weighted?<br />
Solutions:<br />
System:<br />
=<br />
Matrix Equation:<br />
6) At the lake, Curtis caught three fish. He wanted to weigh<br />
the fish individually, but his scale was broken--It could only<br />
read weights between 5 and 10 pounds. So he weighed<br />
the large and medium fish together, and got 7.8 pounds.<br />
The large and small fish weighed 7.0 pounds, and the<br />
small and medium fish were 5.6 pounds.<br />
How much did each fish weigh individually? What was the total weight of all three fish?<br />
Solutions:<br />
=<br />
=<br />
System:<br />
=<br />
Matrix Equation:<br />
©2010, TESCCC 08/01/10 page 27 of 40
Mixing It Up (pp. 5 of 5)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
Continue setting up and solving systems for these situations.<br />
7) On the way home from school, a family enters the drive-through at a fast food restaurant.<br />
Mom: “I need 3 root beers, 2 junior burgers and one deluxe salad.”<br />
Clerk: “That will be $10.62. Please pull around.”<br />
Lucy: “Mom, I don’t want a burger. I’m a vegetarian now!”<br />
Mom: “OK—sorry. Can I get 3 root beers, 1 junior burger and 2 deluxe salads, instead?”<br />
Clerk: “No problem, ma’am. That brings your total to $11.22.”<br />
Mom: “Oh no. I’ve only got $11. Could you take off one of the root beers?”<br />
Clerk “Yes. Two root beers, 1 junior burger, and 2 salads. That’s $10.03.”<br />
What is the cost for each item individually?<br />
Solutions:<br />
=<br />
=<br />
=<br />
System:<br />
Matrix Equation:<br />
8) A box in the textbook warehouse has the given label. It contains<br />
some Algebra II textbooks (each costs $84 and weighs 5.2<br />
pounds), some Chemistry books (each costs $90 and weighs 4.4<br />
pounds), and some Literature books (each costs $75 and weighs 6<br />
pounds). How many of each type of book are in the box?<br />
=<br />
Smart School Publishing<br />
Quantity: 17 books<br />
Weight: 84.4 pounds<br />
Value: $1,449<br />
Solutions:<br />
=<br />
=<br />
System:<br />
Matrix Equation:<br />
©2010, TESCCC 08/01/10 page 28 of 40
Quadratic Quest (pp. 1 of 2)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
2<br />
Quadratic functions have the general equation y ax<br />
If coordinates for three points on the parabola are known,<br />
then the equation can be found using a 33 system of<br />
equations to find a, b, and c.<br />
For example, the given quadratic function passes through<br />
Q(-1, 1.375), R(2.5, 4) and D(3.5, 2.5). This means…<br />
2<br />
ax + b x + c = y<br />
For Q… a(___) 2 + b(___) + c = ____<br />
For R… a(___) 2 + b(___) + c = ____<br />
For D… a(___) 2 + b(___) + c = ____<br />
bx c<br />
, where a 0 .<br />
This system can be written in matrix form and solved to generate the quadratic function.<br />
Matrices Solution Quadratic Function<br />
<br />
a<br />
a<br />
y =<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
b<br />
<br />
<br />
b<br />
<br />
<br />
<br />
Check this on a calculator!<br />
<br />
<br />
<br />
c<br />
<br />
<br />
<br />
c<br />
Use this strategy to solve more problems involving quadratic functions.<br />
1) The parabola shown has its vertex at V(0.5, -2.6). A point on<br />
the left side of the parabola is located at L(-3, 2.3).<br />
What are the coordinates for R, the corresponding point<br />
on the right side?<br />
Set up a system to find the constants a, b, and c.<br />
2<br />
ax + b x + c = y<br />
For L… a(___) 2 + b(___) + c = ____<br />
For V… a(___) 2 + b(___) + c = ____<br />
For R… a(___) 2 + b(___) + c = ____<br />
<br />
<br />
<br />
<br />
<br />
Matrices Solution Quadratic Function<br />
a<br />
a<br />
y =<br />
<br />
<br />
<br />
<br />
<br />
<br />
b<br />
<br />
<br />
b<br />
<br />
<br />
<br />
Check this on a calculator!<br />
<br />
<br />
c<br />
<br />
<br />
<br />
c<br />
From the graph, it looks like the function has x-intercepts at approximately -2 and 3. Find these<br />
values, exactly.<br />
©2010, TESCCC 08/01/10 page 31 of 40
Quadratic Quest (pp. 2 of 2)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 02<br />
2) Bart throws a water balloon off the top of a 40-ft building.<br />
From surveillance photographs, it was determined that, after<br />
he released the balloon, its height at 0.8 seconds was 41.76<br />
feet, and it was 23.04 feet high after 1.6 seconds.<br />
The height (h, in feet) of the water balloon is a quadratic<br />
function of time (x) in seconds. Find this function in the<br />
2<br />
form h( x)<br />
ax bx c .<br />
Time Height<br />
(sec) (ft)<br />
0 40<br />
0.8 41.76<br />
1.6 23.04<br />
? ?<br />
? ?<br />
<br />
<br />
Graph the function in a calculator. After precisely how many seconds did the water balloon<br />
hit the ground?<br />
How high did Bart throw the balloon above the height of the building?<br />
3) The journalism department has put together a magazine that features students’ poems and<br />
short stories as well as pictures of student artwork. They plan on selling the collections as a<br />
fundraiser, but are unsure what to charge. They can generate more revenue if they charge<br />
more for the magazine—but if it’s too expensive, no one will buy it (and they’ll lose money). By<br />
surveying students in English classes, they determine that charging $4 for the books will<br />
generate $712 in revenue, and charging $6 each will create $852 in sales; but at $11 apiece,<br />
they will only bring in $572.<br />
The revenue (R, in dollars) earned from the sale of the magazines is a quadratic function of<br />
2<br />
their individual cost (x). Find this function in the form R( x)<br />
ax bx c .<br />
<br />
Using a calculator, determine how much money they could make it they charged $12 for<br />
each magazine.<br />
<br />
About how much should they charge to earn the most money? According to the function,<br />
what’s the most they could make?<br />
©2010, TESCCC 08/01/10 page 32 of 40
Graphing Inequalities (pp. 1 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 03<br />
The symbol (>,
Graphing Inequalities (pp. 2 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 03<br />
The solution to a system of inequalities is the region that would be included by every inequality.<br />
To graph 1. Lightly shade each individual inequality. (This shows your “work.”)<br />
a solution: 2. Heavily shade the region where they overlap. (This is the solution.)<br />
6)<br />
y<br />
y<br />
3x<br />
5<br />
1 x 2<br />
2<br />
7)<br />
x y 3<br />
y 2x<br />
3<br />
y 3<br />
8)<br />
3x 2y<br />
12<br />
9)<br />
y 2x<br />
1<br />
x 0<br />
x<br />
y 4<br />
y 2x5<br />
x 2<br />
y 3<br />
10) What system of inequalities could be used to create this graph and<br />
solution?<br />
©2010, TESCCC 08/01/10 page 29 of 61
Graphing Inequalities (pp. 3 of 3)<br />
Algebra 2<br />
HS Mathematics<br />
Unit: 05 Lesson: 03<br />
Graph these systems for additional practice.<br />
11)<br />
5x<br />
2y<br />
10<br />
y x<br />
4<br />
12)<br />
y x 2<br />
y<br />
<br />
1<br />
2<br />
x 2y<br />
x 1<br />
10<br />
13)<br />
x 2<br />
y 3<br />
2x<br />
y 3<br />
y 2x<br />
4<br />
14)<br />
y x<br />
3<br />
y 4x<br />
1<br />
3x<br />
2y<br />
8<br />
©2010, TESCCC 08/01/10 page 30 of 61