Réponse:
A= 2x-2 + 2y+4 -2 -2z
= 2x+2y-2z
B=-9x +9xy + 3z +3
= y+3z+3
C=x+y-1 + x+y+1 -x-y+z
= x+y+z
D=2x-2y + 3y-3z + 4z-4x +3x
E=x-xy + y-yz + z-zx + xy+yz+xz
=x+ y+ z
F=x- (1-y-z-1)= x -1 +y +z +1
= x +y +z
(je m'excuse si c'est faux)
