$\begin{array}{l} C = \left( {\dfrac{1}{{x + 2\sqrt x + 1}} + \dfrac{1}{{x - 1}}} \right):\dfrac{{\sqrt x }}{{\sqrt x + 1}}\\ C = \dfrac{{\left( {\sqrt x - 1} \right) + \left( {\sqrt x + 1} \right)}}{{{{\left( {\sqrt x + 1} \right)}^2}\left( {\sqrt x - 1} \right)}}.\dfrac{{\sqrt x + 1}}{{\sqrt x }}\\ C = \dfrac{{2\sqrt x }}{{{{\left( {\sqrt x + 1} \right)}^2}\left( {\sqrt x - 1} \right)}}.\dfrac{{1 + \sqrt x }}{{\sqrt x }}\\ C = \dfrac{2}{{\left( {\sqrt x + 1} \right)\left( {\sqrt x - 1} \right)}} = \dfrac{2}{{x - 1}} \end{array}$
