Page 197 - Algebra 1

Application: Car Wash Fundraiser
The soccer team raises money by washing cars. They charge $5 per car and spend a total of $4 on soap. The table shows the money they raise. Make a graph and use it to find the amount they raise by washing 7 cars. Write the rule in functional notation and use it to check the answer.
Example
5
Math Reasoning
Verify Why is the money raised for 0 cars -$4.00?
Number of Cars Washed, x
0
1
2
3
4
5
Money Raised, f (x)
-4
1
6
11
16
21
SOLUTION
Use the ordered pairs to make a graph. Extend the line beyond x = 7. The y-value on the line is 31 when x = 7, so the soccer team raises $31 by washing 7 cars.
Check theanswerbyevaluatingthe function for x = 7. The rule is $5 times the number of cars x minus $4, or
f(x) = 5x - 4. f(x) = 5x - 4 f(7) = 5(7) - 4
Money Raised by Washing Cars 40
30 20 10
0 10
= 35 - 4 = 31
1 2 3 4 5 6 7 8 Number of Cars Washed
Lesson Practice
a.
(Ex 1)
b.
(Ex 1)
c.
(Ex 3)
Graph y = 2x + 5 using a table of values. Use a graphing calculator to check your table. Decide whether the graph represents a function and whether it is linear or nonlinear.
Graph y = x2 + 1 using a table of values. Use a graphing calculator to check your table. Decide whether the graph represents a function and whether it is linear or nonlinear.
Match the equation y = -2x2 to the correct graph.
y
8
y
4
O
x
-8
-4
4
8
Graph 2
8
4
Gr
aph 1
x
-8
-4
-4
4
8
182 Saxon Algebra 1
-8
Net Earnings ($)