[tex]\bf slope = {{ m}}= \cfrac{rise}{run} \implies \cfrac{f(x_2)-f(x_1)}{x_2-x_1}\impliedby
\begin{array}{llll}
average\ rate\\
of\ change
\end{array}\\\\
-----------------------------\\\\
f(x)=-0.5(x-8)^2-2\quad
\begin{cases}
x_1-4\\
x_2=8
\end{cases}
\\\\\\
\cfrac{f(x_2)-f(x_1)}{x_2-x_1}\implies \cfrac{f(8)-f(-4)}{8-4}[/tex]
