Bonjour
A= (2x+1)2 - (3x-2)(2x+1)
Developper
A = 4x^2 + 4x + 1 - (6x^2 + 3x - 4x - 2)
A = 4x^2 + 4x + 1 - 6x^2 + x + 2
A = -2x^2 + 5x + 3
Factoriser
A = (2x + 1)(2x + 1 - 3x + 2)
A = (2x + 1)(-x + 3)
Resoudre x=0
(2x + 1)(-x + 3) = 0
2x + 1 = 0 ou -x + 3 = 0
2x = -1 ou x = 3
x = -1/2 ou x = 3
Resoudre x=3
-2x^2 + 5x + 3 = 3
-2x^2 + 5x = 3 - 3
-2x^2 + 5x = 0
x(-2x + 5) = 0
x = 0 ou -2x + 5 = 0
x = 0 ou 2x = 5
x = 0 ou x = 5/2
