The monthly cost of driving a car depends on the number of miles driven. Lynn found that in May her driving cost was $380 for480 miand in June her cost was $460for800mi.Assume that there is a linear relationship between the monthly costCof driving a car and the distancexdriven.

(a) Find a linear functionCthat models the cost of drivingxmiles per month.

C(x) =

(b) Draw a graph ofC.

What is the slope of this line?

(c) At what rate does Lynn's cost increase for every additional mile she drives?

$4

per mi