\(A=\frac{4^6.9^5+6^9.120}{-8^4.3^{12}-6^{11}}\)
\(=\frac{\left(2^2\right)^6.\left(3^2\right)^5+2^9.3^9.2^3.3.5}{-\left(2^3\right)^4.3^{12}-2^{11}.3^{11}}\)
\(=\frac{2^{12}.3^{10}+2^{12}.3^{10}.5}{-2^{12}.3^{12}-2^{11}.3^{11}}\)
\(=\frac{2^{12}.3^{10}.\left(1+5\right)}{-2^{11}.3^{11}.\left(2.3+1\right)}\)
\(=\frac{2.6}{-3.7}=\frac{-4}{7}\)