Réponse :
Explications étape par étape
Bonjour
2x + 5 = -3
2x = -3 - 5
x = -8/2
x = -4
3x + 8 = 3 - 2x
3x - 2x = 3 - 8
x = -5
7x = 8 - x
7x + x = 8
8x = 8
x = 8/8
x = 1
5(x + 3) = 2x - 6
5x + 15 = 2x - 6
5x - 2x = -15 - 6
3x = -21
x = -21/3
x = -7
x^2 + 4 = 5x
x^2 - 5x + 4 = 0
x^2 - 2 * x * 5/2 + (5/2)^2 - (5/2)^2 + 4 = 0
(x - 5/2)^2 - 25/4 + 16/4 = 0
(x + 5/2)^2 - 9/4 = 0
(x + 5/2)^2 - (3/2)^2 = 0
(x + 5/2 - 3/2)(x + 5/2 + 3/2) = 0
(x + 2/2)(x + 8/2) = 0
(x + 1)(x + 4) = 0
x + 1 = 0 ou x + 4 = 0
x = -1 ou x = -4
2(3x + 2) = 4 + 6x
6x + 4 = 4 + 6x
6x - 6x = 4 - 4
0 = 0
Vrai quelque soit x
