bonsoir
3 x + 5 = 4
3 x = 4 - 5
3 x = - 1
x = - 1/3
7 x + 8 = 14 x
7 x - 14 x = - 8
- 7 x = - 8
x = 8/7
5 x - 3 = 7 + 5 x
5 x - 5 x = 7 + 3
0 x = 10
pas de solution
a) 14 x + 21 - 23 = - x + 10 x + 5
14 x + x - 10 x = 5 - 21 + 23
5 x = 7
x = 7/5
b) x/3 + 2 = 5 x /6 - 1
2 x + 12 = 5 x - 6
2 x - 5 x = - 6 - 12
-3 x = - 18
x = 6
c) ( x + 1) ( x - 2) = x² + 2
x² - 2 x + x - 2 = x² + 2
x² - x² - x = 2 + 2
- x = 4
x = - 4
