Sagot :
7x-15 = 4x-6
7x-4x = -6+15
3x = 9
x = 9/3
x = 3
5(x+3)-2 = 5+(3x-1)
5x+15-2 = 5+3x-1
5x-3x =5- 15+2-1
2x = -9
x = -9/2
x = -4,5
4/5x + 11 = -5
4/5x = -5-11
4/5x = -16
4 = -80x (on multiplie les deux cotés de l'équation par 5x)
-80x = 4
x = -1/20
x = 0,05