College Algebra 9th txtbk

18 CHAPTER 7 SYSTEMS OF EQUATIONS AND MATRICES
4.
y
(0, 20)
10
(2, 10)
Solution
region
5
(9, 3)
10
(18, 0)
x
5
5x y 20 x y 12
x 3y 18
5.
y
20
5
5
10 20
,
144
7
15
7
x
x 3y 27
5x 8y 120
7-7 Exercises
*Additional answers can be found in the Instructor Answer Appendix.
A
1. If m 0, describe geometrically the graphs of
(A) y mx b (B) y mx b (C) y mx b
2. If m 0, describe geometrically the graphs of
(A) y mx b (B) y mx b
3. What are nonnegativity restrictions? How do they affect the
graph of a system of linear inequalities?
4. In an applied problem, if x is the number of tables produced
and y is the number of chairs produced, how would you interpret
the solution x 12.6 and y 23.2?
In Problems 15–18, match the solution region of each system of
linear inequalities with one of the four regions shown in the figure.
x 2y 8
III
5
y
II
(2, 3)
3x 2y 0
I
In Problems 5–14, graph the solution region of each inequality
and write a verbal description of the solution region.
5. 2x 3y 6 6. 3x 4y 12
7. 3x 2y 18 8. 3y 2x 24
9. y 2 3x 5
10. y 1 3x 2
11. y 8 12. x 5
13. 3 y 2 14. 1 x 3
5
5
15. x 2y 8 16. x 2y 8
3x 2y 0 3x 2y 0
Region IV
Region II
17. x 2y 8 18. x 2y 8
3x 2y 0 3x 2y 0
Region I
Region III
5
IV
x