Bonsoir
résoudre ces équations,
1) 3(2x-5)=12+6x
6x - 15 = 12 + 6x
6x - 15 + 15 = 12 + 6x + 15
6x - 6x = 27 + 6x - 6x
0 = 27
Pas de solution
2) 7(3-2x)=2x(2x-3)
21 - 14x = 4x^2 - 6x
4x^2 - 6x + 14x - 21 = 0
4x^2 + 8x - 21 = 0
(2x)^2 + 2 * 2x * 2 + 2^2 - 25 = 0
(2x + 2)^2 - 25 = 0
(2x + 2 - 5)(2x + 2 + 5) = 0
(2x - 3)(2x + 7) = 0
2x - 3 = 0 ou 2x + 7 = 0
2x = 3 ou 2x = -7
x = 3/2 ou x = -7/2
3) (x+2)^2-(2x-3)^2=0
(x + 2 - 2x + 3)(x + 2 + 2x - 3) = 0
(-x + 5)(3x - 1) = 0
-x + 5 = 0 ou 3x - 1 = 0
x = 5 ou 3x = 1
x = 5 ou x = 1/3
