Explications étape par étape:
) x + 2 = 5
x + 2 = 5 x = 5 - 2 x = 3
b) 3x = 6
3x = 6 x = 6 / 3 x = 2
c) 2x + 7 = 4
2x + 7 = 4 2x = 4 - 7 2x = -3 x = -3 / 2 x = -1.5
d) 4x^2= 2x + 7
4x^2 = 2x + 7 4x^2 - 2x - 7 = 0 (2x + 1)(2x - 7) = 0 2x + 1 = 0 ou 2x - 7 = 0 x = -1/2 ou x = 7/2
e) 5-3x = 11 - 8x
5 - 3x = 11 - 8x -3x + 8x = 11 - 5 5x = 6 x = 6 / 5