NAME _____________________________________________ DATE ____________________________
PERIOD ____________
Homework Practice 6.8.3
Functions and Equations
Write an equation to represent each function.
1.
3.
5.
Input, x
1
2
3
4
5
Output, y
7
14
21
28
35
Input, x
1
2
3
4
5
Output, y
13
26
39
52
65
Input, x
0
1
2
3
4
Output, y
1
6
11
16
21
2.
4.
6.
Input, x
0
1
2
3
4
Output, y
0
9
18
27
36
Input, x
10
20
30
40
50
Output, y
1
2
3
4
5
Input, x
4
8
12
16
20
Output, y
21
37
53
69
85
Graph each equation.
7. y = 5x + 1
8. y = x + 2
9. y = 3x + 3
10. TELEPHONE A cell phone company charges $40 per month plus
$2 for each minute of time used out of the service area. Write the
equation that describes the amount y that a cell phone user would
pay if they used the phone for x minutes out of the service area.
Graph the function.
Course 1 • Chapter 8 Functions and Inequalities
119
NAME _____________________________________________ DATE ____________________________
PERIOD ____________
Study Guide 6.8.3
Functions and Equations
A function table displays input and output values that represent a function. The function displayed in a function table
can be represented with an equation.
Example 1
Write an equation to represent the function.
Examine how the value of each input and output changes.
Input, x
1
2
3
4
5
Output, y
5
10
15
20
25
Input, x
1
2
3
4
5
Output, y
5
10
15
20
25
Each output y is equal to 5 times the input x.
So, the equation that represents the function
is y = 5x.
Example 2
Graph the equation y = 5x.
Select any three values for the input x, for example, 0, 1, and 2.
Substitute these values for x to find the output y.
x
0
1
2
5x
5(0)
5(1)
5(2)
y (x, y)
0 (0, 0)
5 (1, 5)
10 (2, 10)
The ordered pairs (0, 0), (1, 5), and (2, 10) represent the function.
They are solutions of the equation.
Course 1 • Chapter 8 Functions and Inequalities
119