$$ (\frac{3x^2y}{2p^3})^2 = \frac{(3x^2y)^2}{(2p^3)^2} = \frac{3^2(x^2)^2y^2}{2^2(p^3)^2} = \frac{9x^4y^2}{4p^6} $$
Ответ: $$ \frac{9x^4y^2}{4p^6} $$