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sarahlikewoe
2. Forrest Lumber uses the function S(t) = -105t + 840 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? 9 years 10 years 8 years 7 years
When it says "depreciate completely", that means the point where its salvage value, S(t), is equal to 0.
So if S(t) = 0, then 0 = -105t + 840 Then you just need solve for "t"