求解 {l}{-3leqx}{y=|2+x|}{z=y}{text{Solvefor}atext{where}}{a=z}

$$\left. \begin{array} { l } { -3 \leq x }\\ { y = | 2 + x | }\\ { z = y }\\ { \text{Solve for } a \text{ where} } \\ { a = z } \end{array} \right.$$

求解 x 的值

$$\left\{\begin{matrix}x=a-2\text{, }&z=a\text{ and }y=a\text{ and }a\geq 0\\x=-\left(a+2\right)\text{, }&a\leq 1\text{ and }z=a\text{ and }y=a\text{ and }a\geq 0\end{matrix}\right.$$

求解 z 的值

$$z=a$$

$$a\geq 0\text{ and }\left(x=a-2\text{ or }a\leq 1\right)\text{ and }\left(x=a-2\text{ or }x=-\left(a+2\right)\right)\text{ and }y=a$$