Réponse :
Bonjour,
Identité remarquable de la forme:
(a – b)(a + b) ⇔ a² – b²
M = (x + 4)² – 49
= (x + 4)² – 7²
= [(x + 4) + 7][(x + 4) – 7]
= (x + 11)(x – 3)
N = 4 – (1 – 3x)²
= 2² – (1 – 3x)²
= [2 + (1 – 3x)][2 – (1 – 3x)]
= (2 + 1 – 3x)(2 – 1 + 3x)
= (3 – 3x)(1 + 3x)
= 3(1 – x)(1 + 3x)
