Question

$\frac{9}{\sqrt{7} + \sqrt{2} }$

Answer 1

Explicação passo-a-passo:

$\frac{9}{ \sqrt{7} + \sqrt{5}} = \frac{9( \sqrt{7} - \sqrt{5}) }{( \sqrt{7} + \sqrt{5}).( \sqrt{7} - \sqrt{5})} = \frac{9.( \sqrt{7} - \sqrt{5})}{( \sqrt{7})^{2} - ( \sqrt{5})^{2}} = \frac{9.( \sqrt{7} - \sqrt{5})}{7 - 5} = \frac{9.( \sqrt{7} - \sqrt{5})}{2} = \frac{9}{2}.( \sqrt{7} - \sqrt{5})$