Đáp án:
$\begin{array}{l}
Dkxd:x > 0;x \ne 9\\
P = A:B\\
= \dfrac{{x - \sqrt x + 1}}{{3 - \sqrt x }}:\dfrac{{\sqrt x }}{{\sqrt x - 3}}\\
= \dfrac{{x - \sqrt x + 1}}{{3 - \sqrt x }}.\dfrac{{\sqrt x - 3}}{{\sqrt x }}\\
= - \dfrac{{x - \sqrt x + 1}}{{\sqrt x }}\\
= - \dfrac{{{{\left( {\sqrt x - \dfrac{1}{2}} \right)}^2} + \dfrac{3}{4}}}{{\sqrt x }}\\
Do:\left\{ \begin{array}{l}
{\left( {\sqrt x - \dfrac{1}{2}} \right)^2} + \dfrac{3}{4} > 0\\
\sqrt x > 0\left( {khi:x > 0;x \ne 9} \right)
\end{array} \right.\\
\Rightarrow \dfrac{{{{\left( {\sqrt x - \dfrac{1}{2}} \right)}^2} + \dfrac{3}{4}}}{{\sqrt x }} > 0\\
\Rightarrow - \dfrac{{{{\left( {\sqrt x - \dfrac{1}{2}} \right)}^2} + \dfrac{3}{4}}}{{\sqrt x }} < 0\\
\Rightarrow P < 0\\
\Rightarrow P < \left| P \right|
\end{array}$
