[tex] \frac{1}{2 \sqrt{5} } = \frac{ \sqrt{5} }{2 \times 5} \\ \\ - \frac{7}{ \sqrt{7} } = - \frac{7 \sqrt{7} }{7} \\ \\ \frac{9}{ \sqrt{54} } = \frac{9 \sqrt{54} }{54} \\ \\ \frac{2 \sqrt{3} }{ \sqrt{11} } = \frac{2 \sqrt{33} }{11} \\ \\ \frac{ \sqrt{13} }{ - \sqrt{13} } = - \frac{ \sqrt{169} }{13} = - \frac{13}{13} = - 1 \\ \\ \frac{ \sqrt{3} }{ \sqrt{27} } = \frac{ \sqrt{81} }{27} \\ \\ \frac{20}{ - \sqrt{10} } = - \frac{20 \sqrt{10} }{10} \\ \\ \frac{6}{3 \sqrt{2} } = \frac{6 \sqrt{2} }{6} = \sqrt{2} [/tex]
