Question

resultado (×+y+1) (×-y-1)

Answer 1

      (×+y+1) (×-y-1)
     x´2-xy-x+xy-y´2-y+x-y-1
R=x´2-y´2-2y-1

Answer 2

(×+y+1) (×-y-1)=[x+(y+1)][x-(y+1)]=x²-(x+1)²=x²-x-1