Ответ:

[tex] \frac{a - 2}{( \sqrt{a} - \sqrt{2}) ^{2} } = \frac{( \sqrt{a} - \sqrt{2})( \sqrt{a} + \sqrt{2}) }{( \sqrt{a} - \sqrt{2})^{2} } = \frac{ \sqrt{a} + \sqrt{2} }{ \sqrt{a} - \sqrt{2} } [/tex]