5.2.2 Point-Slope Form − Practice (continued)
7. The cost of joining a DVD club and buying DVDs is a linear function of the number of DVDs bought. The cost of 3, 5, and 7 DVDs is shown in the table. Write an equation for the function in slope-intercept form.
8. The cost to fill a car’s tank with gas and get a car wash is a linear function of the capacity of the tank. The costs of a fill-up and a car wash for three different customers are shown in the table. Write an equation for the function in slope- intercept form. Then, find the cost of a fill-up and a car wash for a customer with a truck whose tank size is 29 gallons. Tank size (gal) ( x ) Total cost ($) f ( x ) 9 20.35 16 33.65 20 41.25
Number of DVDs
Cost ($)
3 5 7
12 18 24
9. Find the x -intercept and y -intercept of the line containing the points (2, 12) and ( − 1, 6).
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