\(\frac{2^{15}.9^4}{6^6.8^3}=\frac{2^{15}.\left(3^2\right)^4}{\left(2.3\right)^6.\left(2^3\right)^3}=\frac{2^{15}.3^8}{2^6.3^6.2^9}=\frac{2^{15}.3^8}{2^{15}.3^6}=3^2=9\)
\(\frac{2^{15}.9^4}{6^{6.}.8^3}\)=\(\frac{2^{15}.3^4.3^4}{2^{6.}.3^6.2^9}\) =\(\frac{2^{15}.3^4.3^4}{2^6.2^9.3^4.3^2}\) =\(\frac{2^{15}.3^4.3^2.3^2}{2^{15}.3^4.3^2}\) =\(3^2\) =9