(x-y)^4*(y-x)^3*(x-y)=-(x-y)^4*(x-y)^3*(x-y)=-(x-y)^(4+3+1)=-(x-y)^8(2xyz^2)^2*(-xy^2z)-(-xyz)^3*(5yz)*(-3z)=4x^2y^2z^4*(-xy^2z)+(x^3y^3z^3)*(5yz)*(-3z)=-4x^3y^4z^5-15x^3y^4z^5=-19x^3y^4z^5