me ajudem, por favor.

Hello!!! how are you?
[tex]\frac{3}{\sqrt{5}+ \sqrt{3} } = \frac{3}{\sqrt{5}+ \sqrt{3} } .\frac{\sqrt{5}+ \sqrt{3} }{\sqrt{5}+ \sqrt{3} } = \frac{3\sqrt{5}+ 3\sqrt{3} }{8+2\sqrt{3} \sqrt{5} } = \frac{3+3}{10} = \frac{6}{10} = \frac{3}{5}[/tex]