a) \(\frac{72^3.54^2}{108^4}\)
\(=\frac{\left(2^3.3^2\right)^3.\left(2.3^2\right)^2}{\left(2^2.3^2\right)^4}\)
\(=\frac{2^9.3^6.2^2.6^6}{2^8.3^{12}}=2^3\)
\(=8\)
b) \(\frac{3^{10}.11+3^{10}.5}{3^9.2^4}\)
\(=\frac{3^{10}.\left(11+5\right)}{3^9.2^4}\)
\(=\frac{3^{10}.2^4}{3^9.2^4}\)
\(=3\)