Сократите дробь: a) $$\frac{5 - \sqrt{5}}{\sqrt{30} - \sqrt{6}}$$; б) $$\frac{a - 64}{8 + \sqrt{a}}$$.

а)$$\frac{5 - \sqrt{5}}{\sqrt{30} - \sqrt{6}} = \frac{\sqrt{5}(\sqrt{5} - 1)}{\sqrt{6}(\sqrt{5} - 1)} = \frac{\sqrt{5}}{\sqrt{6}} = \frac{\sqrt{5}\sqrt{6}}{\sqrt{6}\sqrt{6}} = \frac{\sqrt{30}}{6}$$

б)$$\frac{a - 64}{8 + \sqrt{a}} = \frac{(\sqrt{a} - 8)(\sqrt{a} + 8)}{8 + \sqrt{a}} = \sqrt{a} - 8$$