-3/4(-2x^2y)^2乘以(-1/3xy)-(-xy)^3乘以(-x^2)
=(-3/4)*(-1/3) *4(x^4)(y^2)×(xy) -(x^3)(y^3)×(x^2)
=(x^5)(y^3) -(x^5)(y^3)
=0