@Moonnek2008
#Hoidap247
$\text{c.$\frac{4^{5}.9^{4}-2.6^{9}}{2^{10}.3^{8}+6^{8}.20}$}$
$\text{=$\frac{2^{10}.3^{8}-2.2^{9}.3^{9}}{2^{10}.3^{8}+2^{8}.3^{8}.2^{2}.5}$}$
$\text{=$\frac{2^{10}.3^{8}-2^{10}.3^{9}}{2^{10}.3^{8}+2^{10}.3^{8}.5}$}$
$\text{=$\frac{(2^{10}.3^{8}).(1-3)}{(2^{10}.3^{8}).(1+5)}$}$
$\text{=$\frac{1-3}{1+5}$}$
$\text{=$\frac{-2}{6}$}$
$\text{=$\frac{-1}{3}$}$
