Réponses

2014-09-28T18:03:50+02:00
Tester l'égalité -x - 4.5 = 3x + 7.5 pour :
A) x=1
-x - 4.5 = 3x + 7.5
-1 -4.5 = 3*1 +7.5
-5.5 = 10.5

donc fausse

b) x = -3
-x - 4.5 = 3x + 7.5
-(-3) -4.5 = 3(-3) -7.5
3 -4.5 =  -9 -7.5
-1.5 = -16.5

faux
c) x = -,5
-x - 4.5 = 3x + 7.5
-(-0.5) -4.5  = 3(-0.5) +7.5
0.5-4.5 = -1.5+7.5
-3.5 = 6

faux