\[\left( 3x^{3}y^{4} \right)^{3}\ :\left( 3xy^{2} \right)^{2} =\]
\[= 3^{3}y^{12}x^{9}\ :3^{2}x^{2}y^{4} = 3^{1}x^{7}y^{8} =\]
\[= 3x^{7}y^{8}\]