7th Grade Math

394 Linear Functions

= Step-by-Step Solutions begin on page R1.

Extra Practice begins on page EP2.

Example 1 Find the constant rate of change for each table.

3. Time (s) Distance (m)
   0 6
   112
   218
   324
   4. Time (h) Wage ($)
   0 0
   1 9
   218
   327


4. Cost ($) 38 50 62 74 86
   Minutes 1,000 1,500 2,000 2,500 3,000

Example 2 Find the constant rate of change for each graph.

6.

Cost ($)

9

12

15

6

3

0

18

21

24

27

30

1234

Number of Shirts

(1, 9)

(2, 18)

(3, 27)

Cost of T-Shirts^77

Length of Ramp (in.)

75

100

125

50

25

0

150

175

200

225

250

3 6 121824 9 15 21

Height of Ramp (in.)

Access Ramps

(6, 72)

(12, 144)

(18, 216)

B 8. WATER At 1:00 p.m., the water level in a pool is 13 inches. At 2:30 p.m., the

water level is 28 inches. What is the constant rate of change?

99 GRAPHIC NOVEL Refer to the lap times for

Exercises a and b.

Let’s calculate Seth’s

times.

a. How long does it take Seth to complete 1 mile if 20 laps equal 5 miles?

Write the constant rate of change in miles per second.

b. Graph the distance and time on a coordinate plane with the distance

on the y-axis and the time on the x-axis.

391_400_C07_L2_895130.indd 394 12/31/09 4:26 PM