Réponses

2014-06-15T20:50:03+02:00
Bonsoir

(3x +7) + (3x +5) = 0
3x +7 + 3x +5 = 0
6x = - 5 -7
6x = -12
x = - 2

(3x+7)(3x+5) = 0
soit 3x +7 = 0 donc 3x = - 7 et x = - 7/3
3x +5 = 0 donc 3x = -5 et x = - 5/3

25x² = 20x -4
25x² - 20x  + 4 = 0
(5x - 2)(5x-2) = 0
5x -2 = 0
5x = 2
x = 2/5

(2x-6)² = 4
(2x -6 -2)(2x -6+2) = 0
(2x -8) (2x -4) = 0
soit 2x -8 = 0
2x = 8
x = 8/2
x = 4

soit 2x -4 = 0
2x = 4
x = 2