Tolong dibantu ya kak?

[tex] \frac{3}{6 + \sqrt{5} } = \frac{3}{6 + \sqrt{5} } \times \frac{6 - \sqrt{5} }{6 - \sqrt{5} } \\ = \frac{3(6 - \sqrt{5}) }{36 - 5} \\ = \frac{18 - 3 \sqrt{5} }{31} [/tex]
[tex] \frac{9}{ \sqrt{3} } = \frac{9}{ \sqrt{3} } \times \frac{ \sqrt{3} }{ \sqrt{3} } = \frac{9 \sqrt{3} }{3} = 3 \sqrt{3} [/tex]