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Bonjour je ne comprend pas

Factoriser
A=(3x+1)²-4
B=(2x-3+(2x-3)²
C=x²-4+(x-2)(2x+1)


Répondre :

bonjour,

A=(3x+1)²-4 = a²-b² qu'on facto (a-b)(a+b)
(3x+1-2)(3x+1+2) =
(3x-1)(3x+3) =
3(3x-1)(x+1)

B=(2x-3+(2x-3)²
  = 1(2x-3+(2x-3)²
(2x-3)(1+2x-3)=
(2x-3)(2x-2)=
2(2x-3)(x-1)

C=x²-4+(x-2)(2x+1)
x²-4  =a²-b² =(x-2)(x+2)
(x-2)(x+2+2x+1) =
(x-2)(3x+3)=
3(x-2)(x+1)


salut,

A=(3x+1)²-4 = (3x+1)² -2² = (3x+1-2) (3x+1+2) = (3x-1) (3x+3) = 3 (3x-1) (x+1)

B=(2x-3)+(2x-3)² = (2x-3) [1+(2x+3)] = (2x+3) (2x+4) = 2 (2x+3)(x+2)

C=x²-4+(x-2)(2x+1) = (x-2) (x+2) +(x-2)(2x+1) = (x-2) [(x+2)+(2x+1)] = (x-2) (3x+3) =3 (x-2) (x+1)