Forrest Lumber uses the function S(t) = -105t + 945 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?

Question

Forrest Lumber uses the function S(t) = -105t + 945  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?

stamp · Answer

It was worth 945, but loses 105 dollars in value every t years. 

How many years t will it take to depreciate 945 dollars?

S(t) = -105t + 945

105t = 945

t = 945 / 105 years