3xy^2(-1/3x^2y+4x^3y^2)-4x^2y(-3/4xy^2)(-4xy)=-x^3y^3+12x^4y^4+3x^3y^3(-4xy)=-x^3y^3+12x^4y^4-12x^4y^4=-x^3y^3 =-(-3)^3(1/3)^3=1
