Factoriser x^2 + 4x - 12. SVP !

Bonjour,

Factoriser : x^2 + 4x - 12

On calcule le discriminant :
Delta = b^2 - 4ac

Delta = 4^2 - 4 * 1 * (-12)
Delta = 16 + 48
Delta = 64
Vdelta = V64 = 8 > 0 donc deux solutions possibles

X1 = (-b - Vdelta)/(2a)
X2 = (-b + Vdelta)/(2a)

X1 = (-4 - 8)/(2 * 1) = -12/2 = -6
X2 = (-4 + 8)/(2 * 1) = 4/2 = 2

x^2 + 4x - 12 = (x + 6)(x - 2)

Bonjour,

Factoriser:

[tex]x^2+4x-12\\=x^2+(6x-2x)-12\\=x(x+6)-2(x+6)\\=(x+6)(x-2)[/tex]