\[\left( \frac{2x^{4}}{y^{9}} \right)^{- 3} \cdot \left( x^{- 2}y \right)^{- 6} =\]
\[= \left( \frac{y^{9}}{2x^{4}} \right)^{3} \cdot \left( x^{12}y^{- 6} \right) =\]
\[= \frac{y^{27} \cdot x^{12} \cdot y^{- 6}}{8x^{12}} = \frac{1}{8}y^{21}\]