# Math Help - rates of change

1. ## rates of change

hi, i need help on how to set up this question

Determine the average rate of change of the cubic function f(x)= $-4x^3$ for the intervals, x = 1.5 to x = 2.0

2. Originally Posted by extraordinarymachine
hi, i need help on how to set up this question

Determine the average rate of change of the cubic function f(x)= $-4x^3$ for the intervals, x = 1.5 to x = 2.0
$\frac{f(2) - f(1.5)}{2 - 1.5} = \frac{-4(2)^3 - [-4(1.5)^3]}{.5} =$ ... finish