Đáp án:$x \in \left\{ {0;1;2;3;4;5;6;7;8} \right\}$
Giải thích các bước giải:
$\begin{array}{l}
Dkxd:\left\{ \begin{array}{l}
x \ge 0\\
3 - \sqrt x \ne 0
\end{array} \right. \Rightarrow \left\{ \begin{array}{l}
x \ge 0\\
x \ne 9
\end{array} \right.\\
\dfrac{2}{{3 - \sqrt x }} > \dfrac{1}{2}\\
\Rightarrow \dfrac{2}{{3 - \sqrt x }} - \dfrac{1}{2} > 0\\
\Rightarrow \dfrac{{4 - 3 + \sqrt x }}{{2\left( {3 - \sqrt x } \right)}} > 0\\
\Rightarrow \dfrac{{\sqrt x + 1}}{{2\left( {3 - \sqrt x } \right)}} > 0\\
\Rightarrow 3 - \sqrt x > 0\left( {do:\sqrt x + 1 \ge 1 > 0} \right)\\
\Rightarrow \sqrt x < 3\\
\Rightarrow x < 9\\
\Rightarrow 0 \le x < 9\\
\Rightarrow x \in \left\{ {0;1;2;3;4;5;6;7;8} \right\}
\end{array}$
