\(\dfrac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^{10}}\)
\(=\dfrac{2^{10}\cdot3^8-2^{10}\cdot3^9}{2^{10}\cdot3^8+2^{10}\cdot3^{10}}\)
\(=\dfrac{2^{10}\cdot3^8\left(1-3\right)}{2^{10}\cdot3^8\left(1+3^2\right)}=-\dfrac{2}{10}=-\dfrac{1}{5}\)
\(\dfrac{4^5.9^4-2.6^9}{2^{10}.3^8+6^{10}}\)
\(=\dfrac{\left(2^2\right)^5.\left(3^2\right)^4-2.\left(2.3\right)^9}{2^{10}.3^8+\left(2.3\right)^{10}}\)
\(=\dfrac{2^{10}.3^8-2.2^9.3^9}{2^{10}.3^8+2^{10}.3^{10}}\)
\(=\dfrac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8.\left(1+3^2\right)}\)
\(=\dfrac{2^{10}.3^8.\left(1-3\right)}{2^{10}.3^8.10}\)
\(=\dfrac{-2}{10}\)
\(=\dfrac{-1}{5}\)
