a) \(=\frac{\left(3.15\right)^{10}.5^5.5^{15}}{75^5}=\frac{15^5.5^5.3^{10}.15^5.5^{15}}{75^5}=\frac{\left(15.5\right)^5.\left(15.5\right)^{15}.3^{10}}{75^5}=\frac{75^{20}.3^{10}}{75^5}=75^{15}.3^{10}\)
b) \(\frac{2^{15}.9^4}{9^4.9^2.\left(2^3\right)^3}=\frac{2^9.9^4}{2^9.9^4.9^2}=\frac{1}{81}\)