3)
[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}\\\\
-------------------------------\\\\
%x2-4x; -2 ≤x≤ 4
f(x)=x^2-4x \qquad
\begin{cases}
x_1=-2\\
x_2=4
\end{cases}\implies \cfrac{f(4)-f(-2)}{4-(-2)}
\\\\\\
\cfrac{[4^2-4(4)]~~-~~[(-2)^2-4(-2)]}{4+2}\implies \cfrac{[16-16]~~-~~[4+8]}{6}
\\\\\\
\cfrac{0-12}{6}\implies \cfrac{-12}{6}\implies \cfrac{-2}{1}\implies -2[/tex]
