[tex]\bf slope = {{ m}}= \cfrac{rise}{run} \implies
\cfrac{{{ f(x_2)}}-{{ f(x_1)}}}{{{ x_2}}-{{ x_1}}}\impliedby
\begin{array}{llll}
\textit{average rate}\\
\textit{ of change}
\end{array}
\\\\\\
H(x)=x^3-64x^2\quad
\begin{cases}
x_1=-2\\
x_2=0
\end{cases}\implies \cfrac{H(x_2)-H(x_1)}{x_2-x_1}[/tex]