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\(\left ( \sqrt{x}+\sqrt{y}-\dfrac{2 \sqrt {xy}}{\sqrt{x}+\sqrt{y}}\right ) : \left( \dfrac{\sqrt{x}-\sqrt{y}}{\sqrt{x}+\sqrt {y}}+\dfrac{\sqrt{y}}{\sqrt{x}}\right ) =\) [ \(\sqrt x\) | \(\frac{\sqrt x}{\sqrt x+ \sqrt y}\) | \(\frac{(\sqrt x-\sqrt y)}{(\sqrt x+ \sqrt y)\sqrt x}\) | \(\frac{\sqrt x}{\sqrt x- \sqrt y}\) ]