## Precalculus (6th Edition) Blitzer

$-1$
The average rate of change from $x_1=-4$ to $x_2=4$ can be found by dividing the change in the value of $y$ ($y_2-y_1$) by the change in the value of $x$ ($x_2-x_1$). Thus, the average rate of change from $x_1=-4$ to $x_2=4$ is: $=\dfrac{-5-3}{4-(-4)} \\=\dfrac{-8}{4+4} \\=\dfrac{-8}{8} \\=-1$ Thus, the average rate of change of $f$ from $x_1=-4$ to $x_2=4$ is $-1$.