3x^3y^3(-2/3x^2y)^2+(-1/3x^2y)^39xy^2=3x^3y^3(4x^4y^2／9﹚+﹙-1/27﹚·x^6y^3·9xy^2=4x^7y^5／3－x^7y^5／3=x^7y^5 =﹣32
