Respuesta :
f(x) = -x^2 + 3x + 8
f'(x) = -2x + 3
when f(x) is increasing f'(x) > 0
-2x + 3 > 0
-2x > -3
x < 3/2 or 1.5
So the required interval is (-infinity,1.5).The first choice.
f'(x) = -2x + 3
when f(x) is increasing f'(x) > 0
-2x + 3 > 0
-2x > -3
x < 3/2 or 1.5
So the required interval is (-infinity,1.5).The first choice.