a/ ĐKXĐ:\(x\ge0;x\ne4\)
\(Q=\left(\frac{\left(\sqrt{x}+1\right)\left(\sqrt{x}+2\right)-2\sqrt{x}\left(\sqrt{x}-2\right)-5\sqrt{x}-2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\right):\frac{\sqrt{x}\left(3-\sqrt{x}\right)}{\left(\sqrt{x}+2\right)\left(\sqrt{x}+2\right)}\)
\(Q=\frac{x+3\sqrt{x}+2-2x+4\sqrt{x}-5\sqrt{x}-2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}.\frac{\left(\sqrt{x}+2\right)\left(\sqrt{x}+2\right)}{\sqrt{x}\left(3-\sqrt{x}\right)}\)
\(Q=\frac{-\sqrt{x}\left(\sqrt{x}-2\right)}{\sqrt{x}-2}.\frac{\sqrt{x}+2}{\sqrt{x}\left(3-\sqrt{x}\right)}\)
\(Q=\frac{-\sqrt{x}-2}{3-\sqrt{x}}=\frac{\sqrt{x}+2}{\sqrt{x}-3}\)
b/ Để Q=2\(\Leftrightarrow\frac{\sqrt{x}+2}{\sqrt{x}-3}=2\Leftrightarrow\sqrt{x}+2=2\sqrt{x}-6\)
\(\Leftrightarrow\sqrt{x}=8\Leftrightarrow x=64\) (t/m)
c/ Để Q âm\(\Leftrightarrow\frac{\sqrt{x}+2}{\sqrt{x}-3}< 0\)
Có \(\sqrt{x}+2>0\Rightarrow\sqrt{x}-3< 0\Leftrightarrow x< 9\)
Kh ĐKXĐ và KL
