\[\frac{9}{\sqrt{3} - 1} = \frac{9\left( \sqrt{3} + 1 \right)}{\left( \sqrt{3} - 1 \right)\left( \sqrt{3} + 1 \right)} =\]
\[= \frac{9\left( \sqrt{3} + 1 \right)}{3 - 1} = \frac{9\left( \sqrt{3} + 1 \right)}{2} =\]
\[= 4,5\sqrt{3} + 4,5.\]