\(N=\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}=\frac{2^{12}.3^{10}+2^9.3^9.3.5.2^3}{2^{12}.3^{12}-2^{11}.3^{11}}=\frac{2^{12}.3^{10}\left(1+5\right)}{2^{11}.3^{11}\left(2.3-1\right)}=\frac{2^{12}.3^{10}.2.3}{2^{11}.3^{11}.5}=\frac{2^{11}.3^{11}.2^2}{2^{11}.3^{11}.5}=\frac{4}{5}\)