\[\boxed{\mathbf{568\ (568).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ \frac{\left( \sqrt{b} - \sqrt{a} \right)^{2}}{(a - b)\left( \sqrt{a} + \sqrt{b} \right)} =\]
\[= \frac{\left( \sqrt{b} - \sqrt{a} \right)^{2}}{\left( \sqrt{a} - \sqrt{b} \right)\left( \sqrt{a} + \sqrt{b} \right)^{2}} =\]
\[= \frac{- \sqrt{b} + \sqrt{a}}{\left( \sqrt{a} + \sqrt{b} \right)^{2}}\]
\[2)\frac{\sqrt{a} - \sqrt{b}}{a + \sqrt{\text{ab}}} - \frac{\sqrt{a} - \sqrt{b}}{\left( \sqrt{a} + \sqrt{b} \right)^{2}} =\]
\[= \frac{a - b - a + \sqrt{\text{ab}}}{\sqrt{a} \cdot \left( \sqrt{a} + \sqrt{b} \right)^{2}} =\]
\[= \frac{\sqrt{\text{ab}} - b}{\sqrt{a} \cdot \left( \sqrt{a} + \sqrt{b} \right)^{2}}\ \]
\[3)\ \frac{\sqrt{\text{ab}} - b}{\sqrt{a} \cdot \left( \sqrt{a} + \sqrt{b} \right)^{2}}\ :\frac{\sqrt{a} - \sqrt{b}}{a + \sqrt{\text{ab}}} =\]
\[= \frac{\sqrt{b}}{\sqrt{a} + \sqrt{b}}\]
\[1)\ \sqrt{a} + \sqrt{b} - \frac{2\sqrt{\text{ab}}}{\sqrt{a} + \sqrt{b}} =\]
\[= \frac{a + \sqrt{\text{ab}} + \sqrt{\text{ab}} + b - 2\sqrt{\text{ab}}}{\sqrt{a} + \sqrt{b}} =\]
\[= \frac{a + b}{\sqrt{a} + \sqrt{b}}\]
\[2)\ \frac{\sqrt{a} - \sqrt{b}}{\sqrt{a} + \sqrt{b}} + \frac{\sqrt{b}}{\sqrt{a}} =\]
\[= \frac{a - \sqrt{\text{ab}} + \sqrt{\text{ab}} + b}{\sqrt{a} \cdot \left( \sqrt{a} + \sqrt{b} \right)} =\]
\[= \frac{a + b}{\sqrt{a} \cdot \left( \sqrt{a} + \sqrt{b} \right)}\]
\[3)\frac{(a + b) \cdot \sqrt{a} \cdot (\sqrt{a} + \sqrt{b})}{(\sqrt{a} + \sqrt{b})(a + b)} = \sqrt{a}\ \]