$$${\displaystyle \frac{21x^{-4}\cdot 9y^3\cdot 6z^5\cdot x^3\cdot 8z^{-8}}{4y^2\cdot 7x^{-6}\cdot 3y\cdot 18z^{-4}}}$

$\text{o}\text{r}\text{d}\text{n}\text{e}$

${\displaystyle \frac{21\cdot 9\cdot 6\cdot 8\cdot x^3\cdot x^{-4}\cdot y^3\cdot z^5\cdot z^{-8}}{4\cdot 7\cdot 3\cdot 18\cdot x^{-6}\cdot y^2\cdot y\cdot z^{-4}}}$

$\text{k}\text{ü}\text{r}\text{z}\text{e}$

${\displaystyle \frac{\cancel{21}\cdot \cancel{9}\cdot 6\cdot \cancel{8}\cdot x^3\cdot x^{-4}\cdot y^3\cdot z^5\cdot z^{-8}}{\cancel{4}\cdot \cancel{7}\cdot \cancel{3}\cdot \cancel{18}\cdot x^{-6}\cdot y^2\cdot y\cdot z^{-4}}}$

$\text{f}\text{a}\text{s}\text{s}\text{e}\text{z}\text{u}\text{s}\text{a}\text{m}\text{m}\text{e}\text{n}$

${\displaystyle \frac{6\cdot (x^3\cdot x^{-4})\cdot y^3\cdot (z^5\cdot z^{-8})}{x^{-6}\cdot (y^2\cdot y)\cdot z^{-4}}}$

$\text{v}\text{e}\text{r}\text{e}\text{i}\text{n}\text{f}\text{a}\text{c}\text{h}\text{e}$

$6\cdot x^{(3-4+6)}\cdot y^{(3-3)}\cdot z^{(5-8+4)}$

$\text{Vereinfachter Term:}\Rightarrow 6x^{5}z$