\(\dfrac{\left(-0.25\right)^{-5}\cdot9^4\cdot\left(-2\right)^{-3}-2^{-2}\cdot6^9}{2^9\cdot3^6+6^6\cdot40}\)
\(=\dfrac{2^7\cdot3^8-2^8\cdot3^9}{2^9\cdot3^6+2^9\cdot3^6\cdot5}\)
\(=\dfrac{2^7\cdot3^8\cdot\left(-5\right)}{2^9\cdot3^6\cdot6}\)
\(=\dfrac{1}{4}\cdot9\cdot\dfrac{-5}{6}=\dfrac{-45}{24}=\dfrac{-15}{8}\)