\[\frac{3x^{2}}{2y^{2}z^{2}} \cdot \frac{6y^{2}}{7z^{6}}\ :\frac{9xy}{14z^{2}} =\]
\[= \frac{3x^{2} \cdot 6y^{3} \cdot 14z^{2}}{2y^{2}z^{2} \cdot 7z^{6} \cdot 9xy} =\]
\[= \frac{3 \cdot 6 \cdot 14 \cdot x^{2}y^{3}z^{2}}{2 \cdot 7 \cdot 9 \cdot xy^{3}z^{8}} = \frac{2x}{z^{6}}\]