7th Grade Math

380 Linear Functions

Example 1 Copy and complete each function table. Then identify the domain and range.

1. y = 3 x 2. y = 4 x

x 3 x y

13 · 13

23 · 2

33 · 3

4

(^) x 4 x y
04 · 0
14 · 1
2
3

3. MUSIC Jonas downloads 8 songs each month onto his digital music player.
   Make a function table that shows the total number of songs downloaded
   after 1, 2, 3, and 4 months. Then identify the domain and range.

Examples 2 and 3 4. SPORTS The top speed reached by a race car is 231 miles per hour.

a. Write an equation using two variables to show the relationship between

the number of miles m that a race car can travel in h hours.

b. Use your equation to explain how to find the distance in miles the race

car will travel in 3 hours. Then solve.

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

Extra Practice begins on page EP2.

Example 1 Copy and complete each function table. Then identify the domain and range.

5. y = 2 x 6. y = 6 x 77 y = 9 x
   x 2 x y
   02 · 00
   12 · 1
   2
   3

(^) x 6 xy
1
2
3
4
(^) x 9 xy
1
2
3
4
Make a function table for each situation. Then identify the domain
and range.

8. PIZZA A pizza shop sells 25 pizzas each hour. At the same rate, find the
   number of pizzas sold after 1, 2, 3, and 4 hours.


9. TYPING Suppose you can type 60 words per minute. What is the total
   number of words typed after 5, 10, 15, and 20 minutes?

Examples 2 and 3 10. CELL PHONES A cell phone provider charges a customer $40 for each

month of service.

a. Write an equation using two variables to show the relationship between

the total amount charged c after m months of cell phone service.

b. Use your equation to explain how to find the total cost for 6 months of

cell phone service. Then solve.

377_384_C07_L1_895130.indd 380 12/31/09 4:23 PM