Ta có: |x-a|=a
\(\Leftrightarrow\left[{}\begin{matrix}x-a=a\\x-a=-a\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=a+a\\x=-a+a\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=2a\\x=0\end{matrix}\right.\)
Vậy: \(x\in\left\{0;2a\right\}\)