Official solution
\[\begin{aligned}
& f(x)= \begin{cases}x-1, & x \geq 1 \\
1-x & x<0\end{cases} \\
\& g(x)=\left\{\[\begin{array}{|ccc|}e^x & ; \quad x \geq 0 \\ x+1 & ; \quad x \leq 0\end{array}\end{aligned}\]\right.
\]
\[\begin{aligned}
f(g(x)) & = \begin{cases}g(x)-1, & g(x) \geq 1 \\
1-g(x) & g(x)<1\end{cases} \\
\& =\left\{\[\begin{array}{|ccc|}e^x-1 & x \geq 0 \\ -x & x<0\end{array}\end{aligned}\]\right.
\]