Réponse :Bonjour,
A = 3x² - 8x² - 5x - 2x +4 - 12
= x² (3-8) - x(5+2) - 8
= -5x² -7x - 8
B = 7 - (4x * 8) + 8x
= 7 - (32x) + 8x
= 7 - 32x+8x
= -24x + 7
Bon courage :)
