\(\begin{array}{l}
\quad = \dfrac{5}{\sqrt3 - 2\sqrt2} - \dfrac{5}{\sqrt3 +\sqrt8}\\
= - 5\left(\dfrac{1}{\sqrt3 - \sqrt8} + \dfrac{1}{\sqrt3 + \sqrt8}\right)\\
= - 5\cdot \dfrac{\sqrt3 + \sqrt8 + \sqrt3 - \sqrt8}{\left(\sqrt3 - \sqrt8\right)\left(\sqrt3 + \sqrt8\right)}\\
= - 5\cdot \dfrac{2\sqrt3}{-5}\\
= 2\sqrt3
\end{array}\)