Question

Racionalize.
√2/√5?
√7/2√6?

Answer 1

Racionalize.√2 = √2.√5 = √2.5==> √10
√5     √5.√5     √25          5
=====================================

 √7  =  √7.√6 =  √7.6 = √42  ==> √42
2√6     2√6.√6    2√36    2.6          12

Answer 2

Olá Luana,
Como vai?
Vamos lá:

$\frac{\sqrt{2}}{\sqrt{5}}\to \frac{\sqrt{2}}{\sqrt{5}}\times \frac{\sqrt{5}}{\sqrt{5}}\to \frac{\sqrt{10}}{\sqrt{25}}\to \boxed{\frac{\sqrt{10}}{5}}\\ \\ \frac{\sqrt{7}}{2\sqrt{6}}\to \frac{\sqrt{7}}{2\sqrt{6}}\times \frac{\sqrt{6}}{\sqrt{6}}\to \frac{\sqrt{42}}{2\sqrt{36}}\to \frac{\sqrt{42}}{2\times 6}\to \boxed{\frac{\sqrt{42}}{12}}$

Espero ter ajudado.