bjr
les inconnues x Ă gauche, les constantes Ă droite
5x + 7 = 2x - 2
5x - 2x = - 2 - 7
3x = -9
x = -9/3
x = -3
on a bien 5*(-3) + 7 = -15 + 7 = - 8
et 2*(-3) - 2 = - 6 - 2 = - 8
donc c'est correct
2x - 5 = 5x + 1
2x - 5x = 1 + 5
-3x = 6
x = -6/3
x = -2
5x - 6 = -x + 3
5x + x = 3 + 6
6x = 9
x = 9/6
x = 1,5
