A company purchased a machine for 80,000, and they would like to use it for 5 years.

Show, using the straight line function, the depreciation of the machine over 5 years.

What would the depreciation of the machine be after 1 1/2 years?

I am afraid that I do not even know how to start this problem, and there are no examples in my text book.

I can picture the graph of this function as a straight line starting high on the y-axis and decreasing as x gets larger.

But, I do not know how to express this as a straight line function.

How do I begin?