Đáp án:
$\begin{array}{l}
Dkxd:\left\{ \begin{array}{l}
x \ge 0\\
x \ge 1\\
\sqrt x \ne \sqrt {x - 1} \\
\sqrt {x - 1} \ne \sqrt 2 \\
\sqrt 2 \ne \sqrt x \\
\sqrt {2x} - x \ne 0
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x \ge 1\\
x \ne x - 1\left( {tm} \right)\\
x - 1 \ne 2\\
2 \ne x\\
\sqrt x \left( {\sqrt 2 - x} \right) \ne 0
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x \ge 1\\
x \ne 3\\
x \ne 2\\
x \ne 0
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x \ge 1\\
x \ne 2\\
x \ne 3
\end{array} \right.\\
Vậy\,x \ge 1;x \ne 2;x \ne 3
\end{array}$
