Réponse :
Explications étape par étape
(a - b)^2 = a^2 - 2ab + b^2
(a + b)^2 = a^2 + 2ab + b^2
(a - b)(a + b) = a^2 - b^2
Bonsoir
Developper :
A = 7(x + 2)^2 - (3x + 1)(x - 2)
A = 7(x^2 + 4x + 4) - (3x^2 - 6x + x - 2)
A = 7x^2 + 28x + 28 - 3x^2 + 5x + 2
A = 4x^2 + 33x + 30
B = (2x - 5)^2 + (3x - 2)(3x + 2)
B = 4x^2 - 20x + 25 + 9x^2 - 4
B = 13x^2 - 20x + 21
Factoriser :
A = (x - 1)(x + 2) + (x - 1)(x + 5)
A = (x - 1)(x + 2 + x + 5)
A = (x - 1)(2x + 7)
B = (3x + 1)(-4x + 5) - 2(3x + 1)
B = (3x + 1)(-4x + 5 - 2)
B = (3x + 1)(-4x + 3)
Résoudre :
5x = 0
x = 0
(2x + 5)/4 = 3
2x + 5 = 3 * 4
2x = 12 - 5
x = 7/2
x = 3,5
