A careful analysis of the cost of operating an automobile was conducted by accounting manager Dia Bandaly. The following model was developed: y - 4,000 + 0.20x, where y is the annual cost and x is the miles driven. a) If the car is driven 15,000 miles this year, the forecasted cost of operating this automobile = (enter your response as a whole number). b) If the car is driven 25,000 miles this year, the forecasted cost of operating this automobile = (enter your response as a whole number)