Answer
$$3$$
Work Step by Step
We write the general formula for the average rate of change from $x=m$ to $x=n$ as: $\dfrac{f(n)-f(m)}{n-m}$
Apply this formula to obtain:
$\dfrac{f(4)-f(0)}{4-0}=\dfrac{(3(4)-5)-(3(0) -5)}{4} \\=\dfrac{7-(-5)}{4} \\=\dfrac{7+5}{4} \\=\dfrac{12}{4} \\=3$
