Suppose you own a car that is 40 months old. From an automobile dealer's "Blue Book" you find that its trade-in value is $3200. From an old Blue Book you find

that its trade-in value 10 months ago was $4700.

a. Write a function expressing trade-in value as a function of the cars age in

months.

b. You plan to get rid of the car when its trade-in value drops to $1000. How

much longer should you keep the car?

c. What does the slope of your function represent in the real world? Why is

it negative?

d. When do you predict that car will be worthless? How do you know this?

e. According to your model, what was the trade-in value of the car when it

was new?