Réponse :
A =(x+3)(9+x+3)
A =(x+3)(x+12)
B = (x-6-4)(x-6+4)
B = (x-10)(x-2)
C = [(2x-7)-3(2x-7)][(2x-7)+3(2x-7)]
C =(2x-7-6x+21)(2x-7+6x-21)
C =(-4x+14)(10x-28)
C= 4(-2x+7)(5x-14)
Explications étape par étape
A = (x+3)(9+x+3) = (x+3)(x+12)
B = (x-6-4)(x-6+4) = (x-10)(x-2)
C = (2x-7)(2x-7-3) = (2x-7)(2x-10) = 2(2x-7)(x-5)
Bonne soirée
