Ecology—Chemical Run-Off: The amount of toxic material entering Lake Formica is related to...

Ecology—Chemical Run-Off: The amount of toxic material entering Lake Formica is related to the number of years that the Bristine Chemical Company has been operating and can be modeled by

where x represents the number of years that the company has been operating and f(x) represents the amount of toxic material entering the lake, measured in gallons.

(a) Evaluate f(15) and interpret.

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(b) Determine f′( x).

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(c) Evaluate f′(15) and interpret.