Janelle is planning to rent a car while on vacation. The equation $$ C=0.32 m+15 $$ models the relation between the cost in dollars, $C$, per day and the number of miles, $m,$ she drives in one day.
(a) Find the cost if Janelle drives the car 0 miles one day.
(b) Find the cost on a day when Janelle drives the car 400 miles.
(c) Interpret the slope and C-intercept of the equation.
(d) Graph the equation.