Question

Just an Average Rate of Change problem im needing help with

Answer 1

We going to use the AROC formula

$\frac{f(b)-f(a)}{b-a}$

Being a=-2 and b=-4

Let's find the numerator

$\begin{gathered} f(b)=-3\left(-4\right)^3+12(-4)-21 \\ f(b)=123 \end{gathered}$$\begin{gathered} f(a)=-3\left(-2\right)^3+12(-2)-21 \\ f(a)=-21 \end{gathered}$

Replacing

$\frac{123-(-21)}{-4-(-2)}=-\frac{144}{2}=-72$

Answer: -72