\( a)P = \dfrac{{\sqrt x + 1}}{{x - 1}} - \dfrac{{x + 2}}{{x\sqrt x - 1}} - \dfrac{{\sqrt x + 1}}{{x + \sqrt x + 1}}\\ = \dfrac{{\sqrt x + 1}}{{\left( {\sqrt x - 1} \right)\left( {\sqrt x + 1} \right)}} - \dfrac{{x + 2}}{{\left( {\sqrt x - 1} \right)\left( {x + \sqrt x + 1} \right)}} - \dfrac{{\sqrt x + 1}}{{x + \sqrt x + 1}}\\ = \dfrac{{x + \sqrt x + 1 - \left( {x + 2} \right) - \left( {\sqrt x - 1} \right)\left( {\sqrt x + 1} \right)}}{{\left( {\sqrt x - 1} \right)\left( {x + \sqrt x + 1} \right)}}\\ = \dfrac{{\sqrt x - x}}{{\left( {\sqrt x - 1} \right)\left( {x + \sqrt x + 1} \right)}}\\ = \dfrac{{ - \sqrt x \left( {\sqrt x - 1} \right)}}{{\left( {\sqrt x - 1} \right)\left( {x + \sqrt x + 1} \right)}}\\ = \dfrac{{ - \sqrt x }}{{x + \sqrt x + 1}} \)
Ai giúp mình câu b nữa đc ko ạ, mình mắc là mắc b thôi ạ