## Precalculus (10th Edition)

$3$
The general formula for the average rate of change from $x=a$ to $x=b$ is $\frac{f(b)-f(a)}{b-a}.$. Using the formula above gives: $\frac{f(4)-f(0)}{4-0}=\frac{(3\cdot4-5)-(3\cdot 0 -5)}{4}=\frac{7-(-5)}{4}=\frac{7+5}{4}=\frac{12}{4}=3$