TeX source:

\begin{aligned}&\mathbf{D}(|x-2|)= \begin{cases}+1 & \text { if } x > 2 \\\text { undefined } & \text { if } x = 2 \\-1 & \text { if } x < 2\end{cases} \\&D(|2 x|)= \begin{cases}+2 & \text { if } x > 0 \\\text { undefined } & \text { if } x = 0 \\-2 & \text { if } x < 0\end{cases}\end{aligned}