Réponses

2013-04-07T20:03:54+02:00
Tu fai. 0.5x -0.2x= 7.5
0.3x=7.5
x= 7.5 /0.3
X= 25
Meilleure réponse !
2013-04-07T20:07:54+02:00

0.5x = 7.5+0.2x => 0.5x-0.2x = 7.5 => 0.3x = 7.5 => x = 7.5/0.3 = 25