Ta có:\(\frac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}\)=\(\frac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{5.2^9.2^{19}.3^{19}-7.2^{29}.3^{18}}\)=\(\frac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{5.2^{28}.3^{19}-7.2^{29}.3^{18}}\)
=\(\frac{2^{29}.3^{18}.(5.2-9)}{2^{28}.3^{18}.(5.3-7.2)}\)=\(\frac{2^{29}.3^{18}.1}{2^{28}.3^{18}.1}\)=\(\frac{2}{1}\)= 2