Question

Alguém pode me ajudar?

Answer 1

Olá, Gabriela.

$\frac{4}{\sqrt7-\sqrt3}+\sqrt3-\sqrt7=\\\\=\frac{4}{\sqrt7-\sqrt3}\cdot\frac{\sqrt7+\sqrt3}{\sqrt7+\sqrt3}+\sqrt3-\sqrt7=\\\\=\frac{4(\sqrt7+\sqrt3)}{7-3}+\sqrt3-\sqrt7=\\\\=\frac{\not4(\sqrt7+\sqrt3)}{\not4}+\sqrt3-\sqrt7=\\\\=\boxed{2\sqrt3}$