Réponse:
Exercice 30 :
a) 3/4x = 5
4/3 × 3/4x = 5× 4/3
x = 20/3
b) 4x -3 = 11
4x = 11+3
4x = 14
4x × 1/4 = 14 × 1/4
x = 14/4
c) 7-8x = 56
8x = 56 -7
8x = 49
8x/8 = 49/8
x = 49/8
d) 6x -4 = 3x +14
6x -3x = 14 +4
3x = 18
3x/3 = 18/3
x = 6
e) 9 -2x = 11 +4x
-2x -4x = 11 -9
-6x = 2
-6x/-6 = 2/-6
x = -1/3