$\frac{(1,2x^2z^5)^2 * (2x^4z)^3}{0,6xz^8} = \frac{1,44x^4z^{10} * 8x^{12}z^3}{0,6xz^8} = \frac{11,52x^{16}z^{13}}{0,6xz^8} = 19,2x^{15}z^5$