S(t) = -120t + 1,080 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?
In order for S(t) to equal to 0, it would take 9 years. If you multiply 9 times the -120, you will get -1080, then you add that to the +1,080 and the answer is 0.
