Réponse :
Explications étape par étape
Bonjour
Forme développée :
(3-x)^{2}-(3-x)(5+x)
= 9 - 6x + x^2 - (15 + 3x - 5x - x^2)
= 9 - 6x + x^2 - 15 + 2x + x^2
= 2x^2 - 4x - 6
Forme factorisée :
(3-x)^{2}-(3-x)(5+x)
= (3 - x)(3 - x - 5 - x)
= (3 - x)(-2x - 2)
= (3 - x) * (-2)(x + 1)
= (-2)(3 - x)(x + 1)
a)=0
(-2)(3 - x)(x + 1) = 0
3 - x = 0 ou x + 1 = 0
x = 3 ou x = -1
a)=-6.
2x^2 - 4x - 6 = -6
2x^2 - 4x = -6 + 6
2x^2 - 4x = 0
2x(x - 2) = 0
2x = 0 ou x - 2 = 0
x = 0 ou x = 2
