ĐKXĐ: \(\left\{{}\begin{matrix}x\ge0\\x\ne1\end{matrix}\right.\)
A = \(\left(\frac{3\sqrt{x}\left(\sqrt{x}+1\right)-\left(\sqrt{x}-1\right)-3\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\right).\frac{\sqrt{x}+1}{\sqrt{x}+2}\)
= \(\left(\frac{3x+3\sqrt{x}-\sqrt{x}+1-3x+3\sqrt{x}-3\sqrt{x}+3}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\right).\frac{\sqrt{x}+1}{\sqrt{x}+2}\)
= \(\frac{2\left(\sqrt{x}+2\right)}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}.\frac{\sqrt{x}+1}{\sqrt{x}+2}\)
= \(\frac{2}{\sqrt{x}-1}\)
