Réponse :
factoriser les expressions suivantes
A = (7 x + 1)² - (x - 2)² identité remarquable a²-b²=(a+b)(a-b)
= (7 x + 1 + x - 2)(7 x + 1 - x + 2)
= (8 x - 1)(6 x + 3)
A = 3(2 x + 1)(8 x - 1)
B = 4 x² - 5 + (√5 - 2 x)(7 x + 3)
= (2 x)² - (√5)² +(√5 - 2 x)(7 x + 3)
= - ((√5)² - (2 x)²) + (√5 - 2 x)(7 x + 3)
= - ((√5 + 2 x)(√5 - 2 x) + (√5 - 2 x)(7 x + 3)
= (√5 - 2 x)(-√5 - 2 x + 7 x + 3)
= (√5 - 2 x)(5 x + 3 - √5)
C = x² - x + 1/4 - (x - 1/2)(x + 7/2)
= (x - 1/2)² - (x - 1/2)(x + 7/2)
= (x - 1/2)(x - 1/2 - x - 7/2)
= - 4(x - 1/2)
D = x² + 6 x + 8
= x² + 6 x + 8 - 9 + 9
= x² + 6 x + 9 - 1
= (x - 3)² - 1
= (x - 3 + 1)(x - 3 - 1)
= ( x - 2)(x - 4)
E = t² - 14 t + 40
= t² - 14 t + 40 - 49 + 49
= t² - 14 t + 49 - 9
= (t - 7)² - 9
= (t - 7)² - 3²
= (t - 7 + 3)(t - 7 - 3)
= (t - 4)(t - 10)
Explications étape par étape
