Page 753 - Algebra 1

Example
4
Application: Employment
Lena has to earn at least $210 per week from two part-time summer jobs. She can work up to 15 hours per week at Job A, which pays $12 per hour, and can work up to 35 hours per week at Job B, which pays $10 per hour. She is not allowed to work more than 40 hours per week. Graph the possible combinations of hours Lena can work per week.
SOLUTION
Write a system of inequalities where x is the number of hours worked per week at Job A, and y is the number of hours worked per week at Job B.
x ≤ 15
y ≤ 35 12x + 10y ≥ 210
x + y ≤ 40
no more than 15 hours at Job A
no more than 35 hours at Job B
must earn at least $210 per week
cannot work more than 40 hours per week
Math Reasoning
Verify Verify that Lena can make at least $210 working 9 hours at Job A and 20 hours at Job B.
y
x
The region where all four solution sets intersect shows the possible combinations of hours at each job. One possible combination is 9 hours at Job A and 20 hours at Job B.
40 30 20 10
0
10 20 30 40
Hours at Job A
Lesson Practice
Graph each system.
(Ex 1)
a. y > -2x - 1
y ≤ _1 x + 4 5
b. 6y + 6 > -2x y < 2
c. Graph the system on a graphing calculator. (Ex 2)
y ≥ x -6
y ≤ -x + 3
Graph each system.
738 Saxon Algebra 1
(Ex 3)
d.
g.
(Ex 4)
_1 _1 _1
y> 2x-4 e. y< 2x-4 f. y> 2x-4
y > _1 x y > _1 x y < _1 x 222
Brett has $30 with which to buy dried strawberries and dried pineapple for a hiking trip. The dried strawberries cost $3 per pound and the dried pineapple costs $2 per pound. Brett needs at least 2 pounds
of strawberries and 3.5 pounds of pineapple. Graph the possible combinations of pounds of each dried fruit that Brett can buy.
Hours at Job B