\[\frac{\sqrt{5} - \sqrt{3}}{\sqrt{5} + \sqrt{3}} - \frac{\sqrt{5} + \sqrt{3}}{\sqrt{5} - \sqrt{3}} =\]
\[= \frac{\left( \sqrt{5} - \sqrt{3} \right)^{2} + \left( \sqrt{5} + \sqrt{3} \right)^{2}}{5 - 3} =\]
\[= \frac{16}{2} = 8\]