\[\frac{a^{2}}{a^{2} - 25} - \frac{a^{\backslash a + 5}}{a - 5} = \frac{a^{2} - a^{2} - 5a}{(a - 5)(a + 5)} =\]
\[= - \frac{5a}{a^{2} - 25} = \frac{5a}{25 - a^{2}}\]