12-5 Practice B.pdf - MrWalkerHomework

LESSON
12-5
Practice B
Slope
Tell the slope and y-intercept of each line, given its graph.
1. y
2.
1, 4
Tell the slope and y-intercept, given the equation.
3. y 2x 3 4. y 1 x 5 5. y 4x
3
2, 3
6. y 4x 1 7. y x 4 8. y 2x 8
4, 1
4
2
4 2 O 2 4
2
4
(1, 3)
(2, 2)
(3, 1)
x
1 , 5
3
1, 4
4 , 2
3
4
2
2 (0, 2)
4
(3, 2)
x
4 2 O 2 4
y
4, 0
2, 8
LESSON
12-5
Practice C
Slope
Graph and label each pair of points. Draw the line. Find the
slope and y-intercept.
1 1. A(0, 5); B(4, 4) 4 , 5
2. X(1, 3); Y(2, 3)
Tell the slope and y-intercept, given the equation.
3. y 2x 4. y 3 2 x 2 5. y 1 4 x 5
2, 0
4
2
4 2 O 2 4
2
y
A (0, 5)
B(4, 4)
x
3 2 , 2
Graph each line, given the equation. Solve for y when needed.
6. y 1 x 4 7. 3x 2y 4
3
4
2
4 2 O 2 4
2
4
y
2, 1
Y (2, 3)
X (1, 3)
x
1 , 5
4
Graph each line, given the equation.
y
y
9. y 1 2 x 5 10. y 4 x
4
y
4
2
2 O
2
2 4
x
4
4
2
y
2 O 2 4
2
4
4
2
4 2 O 2 4
2
x
Tell the slope of each line containing the following pairs
of points.
8. (7, 1), (5, 3) 2 9. (4, 2), (1, 3) 1 10. (3, 7), (1, 1) 4
2
4 2 O 2 4
2
4
x
Copyright © by Holt, Rinehart and Winston.
46 Holt Middle School Math Course 2
All rights reserved.
Copyright © by Holt, Rinehart and Winston.
47 Holt Middle School Math Course 2
All rights reserved.
LESSON
12-5
Reteach
Slope
The slope of a line is a ratio that measures
the steepness of that line. The sign of the
slope tells whether the line is rising or falling.
You can find the slope of a line by
comparing any two points on that line.
Find the slope of the line between
(2, 1) and (4, 4).
slope r ise
up () or down ()
run
right () or left ()
Use the graph to complete the statements.
1. You have to move up 3 and right 2 to go from one point to the other.
slope r ise
up () or down ()
3 run
right () or left () 2
3
2. The slope of the line is 2
.
You can find the y-intercept of a line by locating the point where it
crosses the y-axis. The y-intercept is the y-coordinate of that point.
3. The line crosses the y-axis at the point ( 0, 2 ). The y-intercept is 2 .
Tell the slope and y-intercept of each line given its graph.
4. y
5.
4
2
(0, 1)
4 2 O 2 4
2
4
4 1
3 4 2 2
(1, 2)
x
4
rise
2
3 up
(2, 1)
4 2 O 2 4
slope u p or
down
3
1 3 slope u p or
down
right
or
left
right
or
left
y-intercept 1
y-intercept 2
Copyright © by Holt, Rinehart and Winston.
48 Holt Middle School Math Course 2
All rights reserved.
2
4
y
2 right
(4, 4)
4
2
4 2 O 2 4
4
y
(2, 2) (2, 2)
x
0 4
run
x
0
LESSON
12-5
Reteach
Slope (continued)
You can find the slope and y-intercept of a line from the equation
when the equation is in the form y mx b. This is called
slope-intercept form. The variable m represents the slope, and
b represents the y-intercept.
y mx b
y 4x 2
y mx b
y 2 3 x
The slope is 4, and the The slope is 2 , and the y-intercept
3
y-intercept is 2. is 0.
Tell the slope and the y-intercept of each line, given the equation.
6. y 5x 4 7. y 1 2 x 1 8. y 3 2 x
5, 4
Using the slope and the y-intercept,
you can graph the equation y 3 x 3.
4
The y-intercept is 3, so the graph
contains the point (0, 3). The slope
is 3 . Starting at (0, 3), count up 3,
4
then 4 to the right. This is the point (4, 0).
Then draw a line through the two points.
9. Graph y 3x 5 using the slope
and y-intercept.
y-intercept 5 ; plot point ( 0, 5 )
slope
From the y-intercept, count down
and right
3
3
1
1 . Plot that point and draw
a line through the two points.
1 2 , 1
3
3 2 , 0
Copyright © by Holt, Rinehart and Winston.
49 Holt Middle School Math Course 2
All rights reserved.
4
2
4 right(4, 0)
x
4 2 O 2 4
3 up
2
(0, 3)
4
4
2
4 2 O 2 4
2
y
y
x
Copyright © by Holt, Rinehart and Winston.
97 Holt Middle School Math Course 2
All rights reserved.