Question

Forrest Lumber uses the function

S(t) = -90t + 810

to determine the salvage value, S(t), in dollars, of a table saw t years after its purchase. How long will it take the saw to depreciate completely?

Answer 1

The saw will depreciate completely in 9 years. Multiply 9 times -90 and you'll get -810, the you add that to the +810 and you'll get 0.