Réponse :
Explications étape par étape
Bjr,
Exercice 9
5a-3a =5 -4
2a = 1
a = 1/2
2a-5+7a = 3a+3
2a+7a-3a =3 +5
6a = 8
a = 8/6 = 4/3
Exercice 10
15x/15 -5/15 = 6x/15 +1/15
15x/15 -6x/15 = 1/15 +5/15
9x/15 = 6/15
3x/5 = 2/5
3x = (2*5)/5 = 10/5 = 2
x = 2/3
exercice 11
-5-3 = 4x-2x
-8 = -2x
-8/-2 = x
x= 4
x/2 -4x/3 = -7-3,5
3x/6 -8x/6 = -10,5
-5x/6 = -10,5
-5x = -10,5 *6 = -63
x = 63/5
3x+12 -7 = 15 -2x
3x+2x = 15 -12 +7
5x = 10
x= 10/5 = 2
