Question

Quero resolver essa questão

Answer 1

Basta racionalizar o denominador:

$\frac{2}{3+\sqrt{7} }=\\\\\frac{2}{3+\sqrt{7} } * \frac{3-\sqrt{7}}{3-\sqrt{7}}=\\\\\frac{6-2\sqrt{7} }{9-7}=\\\\\frac{6-2\sqrt{7} }{2}=\\\\ 3-\sqrt{7}$

=]