Répondre :
b(x)= (12x+14)² - (4x+1)(6x+7)
=4(6x+7)²-(4x+1)(6x+7)
=(6x+7)(24x+28-4x-1)
=(6x+7)(20x+27)
=120x²+302x+189
=4(6x+7)²-(4x+1)(6x+7)
=(6x+7)(24x+28-4x-1)
=(6x+7)(20x+27)
=120x²+302x+189