Đáp án:
c) x=16
Giải thích các bước giải:
\(\begin{array}{l}
a)DK:x \ge 0;x \ne 4\\
\to TXD:D = \left[ {0; + \infty } \right)\backslash \left\{ 4 \right\}\\
b)P = \dfrac{{\left( {\sqrt x + 1} \right)\left( {\sqrt x + 2} \right) + 2\sqrt x \left( {\sqrt x - 2} \right) - 2 - 5\sqrt x }}{{\left( {\sqrt x + 2} \right)\left( {\sqrt x - 2} \right)}}\\
= \dfrac{{x + 3\sqrt x + 2 + 2x - 4\sqrt x - 2 - 5\sqrt x }}{{\left( {\sqrt x + 2} \right)\left( {\sqrt x - 2} \right)}}\\
= \dfrac{{3x - 6\sqrt x }}{{\left( {\sqrt x + 2} \right)\left( {\sqrt x - 2} \right)}}\\
= \dfrac{{3\sqrt x }}{{\sqrt x + 2}}\\
c)P = 2\\
\to \dfrac{{3\sqrt x }}{{\sqrt x + 2}} = 2\\
\to 3\sqrt x = 2\sqrt x + 4\\
\to \sqrt x = 4\\
\to x = 16
\end{array}\)
