x^3+x^2y-xy^2-y^3=x^2(x+y)-y^2(x+y)=(x+y)(x^2-y^2)=(x+y)(x+y)(x-y)=(x+y)^2(x-y)9m^2-6m+2n-n^2=9m^2-n^2-6m+2n=(3m-n)(3m+n)-2(3m-n)=(3m-n)(3m+n-2)x^2-4+12y-9y^2=x^2-(3y-2)^2=(x+3y-2)(x-3y+2)