Đáp án:
$\begin{array}{l}
P = \left( {\dfrac{{x - \sqrt x + 2}}{{x - \sqrt x - 2}} - \dfrac{x}{{x - 2\sqrt x }}} \right):\dfrac{{1 - \sqrt x }}{{2 - \sqrt x }}\\
= \left( {\dfrac{{x - \sqrt x + 2}}{{\left( {\sqrt x - 2} \right)\left( {\sqrt x + 1} \right)}} - \dfrac{{\sqrt x }}{{\sqrt x - 2}}} \right).\dfrac{{\sqrt x - 2}}{{\sqrt x - 1}}\\
= \left( {\dfrac{{x - \sqrt x + 2 - \sqrt x \left( {\sqrt x + 1} \right)}}{{\left( {\sqrt x - 2} \right)\left( {\sqrt x + 1} \right)}}} \right).\dfrac{{\sqrt x - 2}}{{\sqrt x - 1}}\\
= \dfrac{{x - \sqrt x + 2 - x - \sqrt x }}{{\sqrt x + 1}}.\dfrac{1}{{\sqrt x - 1}}\\
= \dfrac{{2 - 2\sqrt x }}{{\left( {\sqrt x + 1} \right)\left( {\sqrt x - 1} \right)}}\\
= \dfrac{{ - 2}}{{\sqrt x + 1}}
\end{array}$
