\( \left( {\dfrac{x}{{\sqrt x - 2}} - \dfrac{{4x - 4\sqrt x }}{{x - 2\sqrt x }}} \right).\dfrac{6}{{{{\left( {\sqrt x - 2} \right)}^2}}}\\ = \left[ {\dfrac{x}{{\sqrt x - 2}} - \dfrac{{4\sqrt x \left( {\sqrt x - 1} \right)}}{{\sqrt x \left( {\sqrt x - 2} \right)}}} \right].\dfrac{6}{{{{\left( {\sqrt x - 2} \right)}^2}}}\\ = \left( {\dfrac{{x - 4\sqrt x + 4}}{{\sqrt x - 2}}} \right).\dfrac{6}{{{{\left( {\sqrt x - 2} \right)}^2}}}\\ = \dfrac{{{{\left( {\sqrt x - 2} \right)}^2}}}{{\sqrt x - 2}}.\dfrac{6}{{{{\left( {\sqrt x - 2} \right)}^2}}} = \dfrac{6}{{\sqrt x - 2}} \)