Answer
$$2$$
Work Step by Step
Given $$f(x)=| x|, \quad[-4,4] $$
The average value is given by
\begin{align*}
M&=\frac{1}{b-a} \int_{a}^{b} f(x) d x\\
&=\frac{1}{4-(-4)} \int_{-4}^{4}|x| d x\\
&=\frac{1}{8} \int_{-4}^{0}-x d x+\frac{1}{8} \int_{0}^{4} x d x\\
&=-\frac{1}{8}\left[\frac{x^{2}}{2}\right]_{-4}^{0}+\frac{1}{8}\left[\frac{x^{2}}{2}\right]_{0}^{4}\\
&=2
\end{align*}