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好像是-1吧是正的呢-3和前面的那个负号负负得正了...正确的...