\(\frac{6^8.2^4-4^5.18^4}{27^3.8^4-3^9.2^{13}}\\ =\frac{2^8.3^8.2^4-2^{2.5}.3^{2.4}.2^4}{3^{3.3}.2^{3.4}-3^9.2^{13}}\\ =\frac{2^{12}.3^8-2^{14}.3^8}{3^9.2^{12}-3^9.2^{13}}\\ =\frac{2^{12}.3^8\left(1-2^2\right)}{3^9.2^{12}.\left(1-2\right)}\\ =\frac{3^8.\left(-3\right)}{3.\left(-1\right)}=3^8\)