\(\frac{20.4^{15}.9^{10}-4.3^{21}.8^{10}}{10.2^{10}.6^{20}-2^{31}.27^7}\)
\(=\frac{4.5.\left(2^2\right)^{15}.\left(3^2\right)^{10}-4.3^{21}.\left(2^3\right)^{10}}{2.5.2^{10}.\left(2.3\right)^{20}-2^{31}.\left(3^3\right)^7}\)
\(=\frac{2^2.5.2^{30}.3^{20}-2^2.3^{21}.2^{30}}{2^{11}.5.2^{20}.3^{20}-2^{31}.3^{21}}\)
\(=\frac{2^{32}.5.3^{20}-2^{32}.3^{21}}{2^{31}.3^{20}.5-2^{31}.3^{21}}\)
\(=\frac{2^{32}.3^{20}.\left(5-3\right)}{2^{31}.3^{20}\left(5-3\right)}\)
\(=2\)