Question

Calculati!

$( \frac{5}{ \sqrt{5} } + \frac{6}{ \sqrt{6} } + \frac{7}{ \sqrt{7} } )* \frac{1}{ \sqrt{5}+ \sqrt{6}+ \sqrt{7} } ;$

Answer 1

(5/√5+6/√6+7/√7) * 1/(√5+√6+√7)  
(√5+√6+√7) * 1/(√5+√6+√7)  =1