a) 3^8.4^8.3^24=3^32.2^16
b) 5^10.3^20.5^30=5^40.3^20
\(a)12^8\cdot9^{12}\)
\(=\left(2^2\cdot3\right)^8\cdot\left(3^2\right)^{12}\)
\(=\left(2^2\right)^8\cdot3^8\cdot3^{24}\)
\(=2^{16}\cdot3^{32}\)
\(=2^{16}\cdot\left(3^2\right)^{16}\)
\(=2^{16}\cdot9^{16}\)
\(=\left(2\cdot9\right)^{16}\)
\(=18^{16}\)
\(b)45^{10}\cdot5^{30}\)
\(=45^{10}\cdot\left(5^3\right)^{10}\)
\(=45^{10}\cdot125^{10}\)
\(=\left(45\cdot125\right)^{10}\)
\(=5625^{10}\)