a rental car costs $25 plus a fixed charge per mile driven. The total charge for 210 miles of use was $67. Write an equation for the cost, C (in dollars), in terms of the miles driven, X.
First, we need acknowledge that 25 is the fixed number.
67 - 25 = 42
210/42 = 5
This means that 5$ is charged every mile.
Thus, we obtain
C = 25 + 5x