Answer:
[tex] \dfrac{x^4y^4}{81} [/tex]
Step-by-step explanation:
[tex] (\dfrac{3}{xy})^{-4} = [/tex]
[tex] = (\dfrac{xy}{3})^{4} [/tex]
[tex] = \dfrac{(xy)^4}{3^4} [/tex]
[tex] = \dfrac{x^4y^4}{81} [/tex]