Question

Over which interval is the graph of f(x) = –x2 + 3x + 8 increasing?

(–∞, 1.5)

(–∞, 10.25)

(1.5, ∞)

(10.25, ∞)

Answer 1

A.

Explanation:

Answer 2

The answer for this question is (-infinity,1.5) because
when f(x) is increasing f'(x) > 0
-2x + 3 > 0
-2x > -3
x< 3/2 or 1.5