a)

$\frac{\left(6^6\cdot 3+4\cdot 6^4\right)\cdot 11}{6^5\cdot 2-6^4}=\frac{\left(6^4\cdot 6^2\cdot 3+4\cdot 6^4\right)\cdot 11}{6^4\cdot 6\cdot 2-1\cdot 6^4}=$ $\frac{\left(6^4\cdot \left(6^2\cdot 3+4\right)\right)\cdot 11}{6^4\left(6\cdot 2-1\right)}=\frac{{\sout{6}}^{\sout{4}}\cdot 11\cdot \left(6^2\cdot 3+4\right)}{{\sout{6}}^{\sout{4}}\cdot \left(6\cdot 2-1\right)}=$