Rút gọn biểu thức sau: A=(1/√x−1−1/√x+1+2√x−4/x−1):1/√x+1 (x≥0;x≠1)

\[A = \left( {\frac{1}{{\sqrt x - 1}} - \frac{1}{{\sqrt x + 1}} + \frac{{2\sqrt x - 4}}{{\left( {\sqrt x - 1} \right)\left( {\sqrt x + 1} \right)}}} \right):\frac{1}{{\sqrt x + 1}}\]

\[A = \frac{{\sqrt x + 1 - \sqrt x + 1 + 2\sqrt x - 4}}{{\left( {\sqrt x - 1} \right)\left( {\sqrt x + 1} \right)}}.\left( {\sqrt x + 1} \right) = \frac{{2\sqrt x - 2}}{{\left( {\sqrt x - 1} \right)\left( {\sqrt x + 1} \right)}}\left( {\sqrt x + 1} \right)\]

\[A = \frac{{2\left( {\sqrt x - 1} \right)}}{{\left( {\sqrt x - 1} \right)\left( {\sqrt x + 1} \right)}}.\left( {\sqrt x + 1} \right) = 2\]