# Calculus: General Differentiation – #482

Question: Suppose that $$x$$ years after its founding in $$1980$$, a certain national consumer’s association had a membership of

$f(x)=10\left( 2{{x}^{3}}-75{{x}^{2}}+900x \right)$

For what year between 1984 and 1994 was the membership the largest? What was the membership at that time? For what year between 1984 and 1994 was the membership the smallest? What was the membership at that time?