Question

1)$\frac{10}{7 \sqrt{6} }$

Answer 1

$\frac{10}{ 7\sqrt{6} }$ x $\frac{ \sqrt{6} }{ \sqrt{6} }$ 
= $\frac{ 10\sqrt{6} }{ 7 (\sqrt{6}) ^{2} }$
= $\frac{10}{7.6}$ = $\frac{10}{42}$,
simplificando por 2: $\frac{5}{21}$