a) \(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}=\frac{\left(0,2.2^2\right)^5}{\left(0,2.2\right)^6}=\frac{0,2^5.2^{10}}{0,2^6.2^6}=\frac{2^4}{0,2}=80\)
b) \(\frac{2^{15}.9^4}{6^4.8^3}=\frac{2^{15}.3^8}{2^4.3^4.2^9}=3^4.2^2=324\)
c) \(\frac{45^{10}.5^{20}}{75^{15}}=\frac{3^{20}.5^{10}.5^{20}}{3^{15}.5^{30}}=3^5=243\)