\[\frac{\sqrt{x^{20}y^{46}z^{50}}}{x^{8}y^{9}z^{12}},\]
\[если\ \ y > 0,\ z < 0\]
\[\ \frac{\sqrt{x^{20}y^{46}z^{50}}}{x^{8}y^{9}z^{12}} = - \frac{x^{10}y^{23}z^{25}}{x^{8}y^{9}z^{12}} =\]
\[= - x^{2}y^{14}z^{13}\]