Question

ДАЮ 90 БАЛОВ нужно срочно.

Answer 1

Смотри..............................

Answer 2

$\displaystyle\bf\\1)\\\\\frac{m-2\sqrt{mn}+n }{m-n}=\frac{(\sqrt{m})^{2} -2\sqrt{mn} +(\sqrt{n})^{2} }{(\sqrt{m})^{2}-(\sqrt{n})^{2}} =\\\\\\=\frac{(\sqrt{m}-\sqrt{n} )^{2} }{(\sqrt{m}-\sqrt{n})\cdot(\sqrt{m}+\sqrt{n})} =\frac{\sqrt{m} -\sqrt{n} }{\sqrt{m}+\sqrt{n} }\\\\\\2)\\\\\Big(\frac{\sqrt{n} }{\sqrt{m} +\sqrt{n} }-\frac{\sqrt{n} -\sqrt{m} }{\sqrt{n} } \Big):\frac{\sqrt{m} }{\sqrt{n} } =$

$\displaystyle\bf\\=\frac{\sqrt{n}\cdot \sqrt{n}-(\sqrt{n} -\sqrt{m})\cdot(\sqrt{m} +\sqrt{n})}{\sqrt{n} \cdot(\sqrt{m} +\sqrt{n} )} \cdot\frac{\sqrt{n} }{\sqrt{m} } =\\\\\\=\frac{n-n+m}{\sqrt{m}\cdot(\sqrt{m} +\sqrt{n} ) }=\frac{m}{\sqrt{m}\cdot(\sqrt{m} +\sqrt{n} ) } =\frac{\sqrt{m} }{\sqrt{m}+ \sqrt{n} }$