\(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)

\(=\frac{\left(2^2\right)^5.\left(3^3\right)^4-2.\left(2.3\right)^9}{2^{10}.3^8+\left(2.3\right)^8.2.10}\)

\(=\frac{2^{10}.\left(3^{12}-3^9\right)}{2^{10}.3^8.\left(1+5\right)}\)

\(=\frac{3^9\left(3^3-1\right)}{3^8.3.2}\)

\(=\frac{3^9.26}{3^9.2}\)

\(=\frac{26}{2}=13\)

\(\frac{4^5\times9^4-2\times6^9}{2^{10}\times3^8+6^8\times20}=\frac{\left(2^2\right)^5\times\left(3^2\right)^4-2\times6\times6^8}{2^2\times2^8\times3^8+6^8\times20}=\frac{2^{10}\times3^8-12\times6^8}{2^2\times\left(2\times3\right)^8+6^8\times20}\)

\(=\frac{2^2\times2^8\times3^8-12\times6^8}{4\times6^8+6^8\times20}=\frac{2^2\times\left(2\times3\right)^8-12\times6^8}{6^8\times\left(4+20\right)}=\frac{4\times6^8-12\times6^8}{6^8\times24}=\frac{6^8\times\left(4-12\right)}{6^8\times24}=\frac{-8}{24}=-\frac{1}{3}\)

a.

A = 72^3.54^2/108^4

A = (72.54:108)^2:108^2.72

A = 36^2:108^2.72

A = (36:108)^2.72

A = (1/3)^2.72

A = 72/9

A = 8

B = \(\frac{3^{10}.11+3^{10}.5}{3^9.2^4}\)

B = \(\frac{3^{10}.\left(11+5\right)}{3^9.2^4}\)

B = \(\frac{3^{10}.16}{3^9.16}\)

B = 3

Có gạch ngang của phân số nhưng hơi mờ,các bạn chịu khó nhìn kĩ nhé:)