Упростить: mn^2-n^2+mn-n; 1\xy (x^3y-2xy^3-x^2y^2)

mn^2-n^2+mn-n=n^2 (m-n)+n (m-n)=(n^2+n) (m-n)=n (n+1) (m-n) 1\xy (x^3y-2xy^3-x^2y^2)=1\xy*xy (x^2-2y^2-xy)=x^2-2y^2-xy=x^2-y^2-y^2-xy=(x-y) (x+y) -y (x+y)=(x+y) (x-y-y)=(x+y) (x-2y)