Đề bài sai chỗ ... - 99 nhé, nếu là .99 sẽ hợp lí hơn =))
\(A=\frac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^{10}.6^{19}-7.2^{29}.27^6}=\frac{5.\left(2^2\right)^{15}\left(3^2\right)^9-2^2.3^{20}.\left(2^3\right)^9}{5.2^{10}.\left(2.3\right)^{19}-7.2^2.\left(3^2\right)^6}\)
\(A=\frac{5.2^{30}.3^{18}-2^2.3^{20}.2^{27}}{5.2^{10}.2^{19}.3^{19}-7.2^{29}.3^{18}}\)
\(A=\frac{5.2^{30}.3^{18}-2^{29}.3^{20}}{5.2^{29}.3^{19}-7.2^{29}.3^{18}}\)
\(A=\frac{2^{29}.3^{18}.\left(5.2-3^2\right)}{2^{29}.3^{18}.\left(5.3-7\right)}\)
\(A=\frac{10-9}{15-7}=\frac{1}{8}\)