Question

Dau coroana....................

Answer 1

$\frac{3}{ \sqrt{7} - \sqrt{4} } = \frac{3}{ \sqrt{7} - 2 }$
Rationalizam numitorul. Amplificam fractia cu
$\sqrt{7} + 2$
si obtinem

$\frac{3 \times (\sqrt{7} + 2) }{ (\sqrt{7} - 2)( \sqrt{7} + 2 ) }$
folosim formula calcului prescurtat si obtinem
$\frac{3( \sqrt{7} + 2) }{7 - 4}$
efectuam scaderea
$\frac{3( \sqrt{7} + 2)}{3}$
simplificam cu 3
$\sqrt{7} + 2$