\(\left\{240-\left[76-\left(9-3\right)^2\right]\right\}:50\)
\(=\left[240-\left(76-6^2\right)\right]:50\)
\(=\left[240-\left(76-36\right)\right]:50\)
\(=\left(240-40\right):50\)
\(=200:50\)
\(=4\)
_______________
\(\dfrac{4^6\cdot3^4\cdot9^5}{6^{12}}\)
\(=\dfrac{2^{12}\cdot3^4\cdot3^{10}}{6^{12}}\)
\(=\dfrac{2^{12}\cdot3^{14}}{2^{12}\cdot3^{12}}\)
\(=\dfrac{1\cdot3^2}{1\cdot1}\)
\(=3^2\)
\(=9\)