Bonjour,
-7x = 4
-7x/-7 = 4/-7
x = -4/7
5x + 27 = 14
5x + 27 - 27 = 14 - 27
5x = -13
5x/5 = -13/5
x = -13/5
9x - 4 = -22
9x - 4 + 4 = -22 + 4
9x = -18
9x/9 = -18/9
x = -2
6x - 4 = 3x + 2
6x - 4 + 4 = 3x + 2 + 4
6x - 3x = 3x + 6 - 3x
3x = 6
3x/3 = 6/3
x = 2
2x - 4 = 5x + 2
2x - 4 - 2x = 5x + 2 - 2x
-4 - 2 = 3x + 2 - 2
-6 = 3x
3x/3 = -6/3
x = -2
2(5x + 6) = x - 8
10x + 12 = x - 8
10x + 12 - x = x - 8 - x
9x + 12 - 12 = -8 - 12
9x = -20
9x/9 = -20/9
x = -20/9
(2x - 5)(x + 3) = 0
Un produit de facteur nul est nul si et seulement si au moins un de ses facteurs est nul :
2x - 5 = 0 ou x + 3 = 0
2x - 5 + 5 = 0 + 5 ou x + 3 - 3 = 0 - 3
2x = 5 ou x = -3
2x/2 = 5/2 ou x = -3
x = 5/2 ou x = -3
(4 + x)/3 = (2x - 1)/5
(4 + x) * 5 = 3 * (2x - 1)
20 + 5x = 6x - 3
20 + 3 + 5x = 6x - 3 + 3
23 + 5x - 5x = 6x - 5x
x = 23
