[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(t) = -16t^2 +32t+90\quad
\begin{cases}
t_1=4\\
t_2=6
\end{cases}\implies \cfrac{f(6)-f(4)}{6-4}[/tex]
