Question

Given the function f(x) = -x^2 +7x + 6, find the interval(s) in which f(x) is decreasing.

Answer 1

Explanation:

f'(x)=-2x+7

f(x) is decreasing if '(x)<0

so -2x+7<0

or 7<2x

or 2x>7

or x>7/2

including end points f(x) is decreasing in [3/2,∞)