Companies often used the method of straight$-$line depreciation to

reduce the value of their assets by a fixed amount each year. The

amount of the reduction depends on the useful life of the asset.

This is generally determined by the company. Suppose a business

selling computer hardware has obtained a fleet of new hybrid cars

for its sales force. Each car costs $$25,000.$ The business estimates

that the useful life of each vehicle is $5$ years. Using the

straight$-$line method, determine the amount of depreciation per

year.a$.$ Determine the value of each car after $3$ years.b$.$ Is this situation, the value of each car, v $,$ is a function

of the age of the car, a$.$ Identify the independent and dependent

variables.c$.$ Use function notation to write a function rule for the value

v$($a$)$ of each car in terms of its age a$.$ d$.$ What is the practical

domain and practical range of the depreciation function?