(a-x)(x-y)(y+x+a)-(y-x)(x-a)(y-x-a)

Question

(a-x)(x-y)(y+x+a)-(y-x)(x-a)(y-x-a)

Answer 1

(а-х)(х-у)(у+х+а)+(х-у)(а-х)(х-у+а)=(х-у)(а-х)(х-у+а+у+х+а)=(х-у)(а-х)(2х+2а+у)

Answer 2

=(ax-ya-x^2+xy)(y+x+a)-(ax-ay-x^2+xy)(y-x-a)=(ax-ya-x^2-xy)((y+x+a)-(y-x-a))= (ax-ya-x^2-xy)(y+x+a-y+x+a)= (ax-ya-x^2-xy)(2x+2a)=(a-x)(x-y)(2x+2a)