Réponses

2013-10-27T21:08:33+01:00
-7 et -5 par exemple car
leur somme : (-5)+(-7)=-5-7=-12
leur différence : (-5)-(-7)=-5+7=2
2013-10-27T21:56:26+01:00
Bonsoir
-a +b = -12
-a -b = 2

-a = -b -12
-b -12 -b = 2
-2b = 2+12
- 2b = 14
-b = 7
b = -7

si b = -7 alors a = -5