Разложите на множители:

1) Xy (x-y) - xz (y-z) - xz (x-y) + yz (y-z)

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

Xy (x-y) - xz (y-z) - xz (x-y) + yz (y-z) = xy (x-y) - xyz+xz²-x²z+xyz+y²z-yz²=

=xy (x-y) - (x-y) (xz+yz-z²) = (x-y) (xy-xz+yz-z²) = (x-y) (y (x-z) - z (x-z)) =

= (x-z) (y-z) (x-y)

(A-X) (X-Y) (Y+X+A) - (Y-X) (X-A) (Y-X-A) = ((A-X) (X-Y)) ((A+X+Y) + A+X-Y) =

= (A-X) (X-Y) (A+X+Y+A+X-Y) = 2 (A-X) (X-Y) (X+A)