\[\frac{\sqrt{x}}{\sqrt{y} - \sqrt{x}}\ \ :\left( \frac{{\sqrt{y}}^{\backslash\text{√}y}}{\sqrt{y} - \sqrt{x}} - \frac{\sqrt{y} + {\sqrt{x}}^{\backslash\text{√}y - \sqrt{x}}}{\sqrt{y}} \right) =\]
\[= \frac{\sqrt{x}}{\sqrt{y} - \sqrt{x}}\ :\frac{y - y + x}{\left( \sqrt{y} - \sqrt{x} \right) \cdot \sqrt{y}} =\]
\[= \frac{\sqrt{x}}{\sqrt{y} - \sqrt{x}} \cdot \frac{\left( \sqrt{y} - \sqrt{x} \right) \cdot \sqrt{y}}{x} = \frac{\sqrt{y}}{\sqrt{x}}.\]