Cho biểu thức P ( x+ 2/ x căn bậc hai x-1 + căn bậc hai x / x+ căn bậc hai x+ 1

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

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

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

\( = \frac{1}{{x + \sqrt x + 1}}\).

2)\(P = \frac{1}{3} \Leftrightarrow \frac{1}{{x + \sqrt x + 1}} = \frac{1}{3} \Leftrightarrow x + \sqrt x - 2 = 0\)

\( \Leftrightarrow \left[ \begin{array}{l}\sqrt x = 1\\\sqrt x = - 2\end{array} \right. \Leftrightarrow x = 1\left( l \right)\).