Page 128 - Algebra 1

Example
4
Application: Wages
The federal minimum wage is about $5 per hour. The total on a minimum- wage worker’s paycheck is dependent on the number of hours worked. The paycheck total can be calculated using the equation y = 5x.
Find the pay for 1, 3, 5, and 8 hours of. Make a graph to represent the equation y = 5x.
SOLUTION
Understand Since a worker makes $5 per hour, a worker’s pay is calculated by multiplying the number of hours worked by 5.
Plan Find the amount of pay, y, when x is equal to 1, 3, 5, and 8 hours. Then graph the ordered pairs.
Solve Substitute 1, 3, 5, and 8 for x.
The ordered pairs are (1, 5), (3, 15), (5, 25), and (8, 40). Graph the ordered pairs. Connect the points with a
smooth line.
Check As the number of hours increases; so does the pay.
The pay should increase steadily, which is shown by the
y = 5x y = 5(3) y = 15
y = 5x y = 5(5) y = 25
y = 5x y = 5(8) y = 40
y = 5x
y = 5(1)
y = 5
The pay for 1, 3, 5, and 8 hours is $5, $15, $25, and $40 respectively.
Math Reasoning
Predict How many hours would someone have worked if they are paid $122.50?
40 30
20
(3, 15)
(8, 40)
straight line on the graph. 10
(1,
Lesson Practice
Graph each ordered pair on a coordinate plane. Label each point.
(Ex 1)
a. (0, 5) c. (-2, 0) e. (5, -1)
b. (-1, -6) d. (-3, 4) f. (2, -4)
For each pair of variables, identify the independent variable and the
dependent variable.
(Ex 2)
g. the amount paid, the number of toys purchased
h. the number of hours worked, the number of yards mowed
i. Complete the table for the equation y = 2x - 1.
(Ex 3)
y
(
5,
25)
x
-3
-2
-1
y
Lesson 20
113
5)
x
4
8