Решение:
a) $$\frac{(5^6)^4 \cdot (5^2)^5}{5^{35}} = \frac{5^{6\cdot4} \cdot 5^{2\cdot5}}{5^{35}} = \frac{5^{24} \cdot 5^{10}}{5^{35}} = \frac{5^{24+10}}{5^{35}} = \frac{5^{34}}{5^{35}} = 5^{34-35} = 5^{-1} = \frac{1}{5} = 0.2$$
б) $$\frac{(3^9)^4}{3^{19} \cdot 3^{15}} = \frac{3^{9\cdot4}}{3^{19+15}} = \frac{3^{36}}{3^{34}} = 3^{36-34} = 3^2 = 9$$