8. Найдите значение дроби: a) $$\frac{13^7}{13^5}=$$ б) $$\frac{\left(-\frac{1}{3}\right)^9}{\left(-\frac{1}{3}\right)^7}=$$

a) $$\frac{13^7}{13^5} = 13^{7-5} = 13^2 = 169$$ б) $$\frac{\left(-\frac{1}{3}\right)^9}{\left(-\frac{1}{3}\right)^7} = \left(-\frac{1}{3}\right)^{9-7} = \left(-\frac{1}{3}\right)^2 = \frac{1}{9}$$