Đáp án:
$\begin{array}{l}
A = \left( {\frac{{2\sqrt x }}{{\sqrt x + 3}} + \frac{{\sqrt x }}{{\sqrt x - 3}} - \frac{{3x + 3}}{{x - 9}}} \right):\frac{{2\sqrt x - 2}}{{\sqrt x - 3}}\\
dkxd:\left\{ \begin{array}{l}
x > 3\\
x \ne 9
\end{array} \right.\\
A = \left( {\frac{{2\sqrt x \left( {\sqrt x - 3} \right) + \sqrt x .\left( {\sqrt x + 3} \right) - 3x - 3}}{{\left( {\sqrt x - 3} \right)\left( {\sqrt x + 3} \right)}}} \right).\frac{{\sqrt x - 3}}{{2\sqrt x - 2}}\\
A = \frac{{2x - 6\sqrt x + x + 3\sqrt x - 3x - 3}}{{\left( {\sqrt x + 3} \right).2.\left( {\sqrt x - 1} \right)}}\\
= \frac{{ - 3\sqrt x - 3}}{{\left( {\sqrt x + 3} \right).2.\left( {\sqrt x - 1} \right)}}\\
= \frac{{ - 3}}{{2\left( {\sqrt x + 3} \right)}}
\end{array}$
