Réponse:
Bsr, Calculons D et E sachant que x+y=-4.
D=-12-(y-x)+4+2y
= -12-y+x+4+2y
= -12+4+x+(2y-y)
= -8+x+(y)
= -8+(x+y)
or x+y=-4 on a :
= -8+(-4)
= -8-4
D=-12.
E=2x-7-(-y+x)
= 2x-7+y-x
= -7+2x-x+y
= -7+x+y
= -7+(x+y)
Or x+y=-4 on a:
= -7+(-4)
= -7-4
E=-11. Bonne journée ))))
