a) A = 3 et B = 4 -> croissant car A > 0
b) A = 2 et B =-6 -> croissant car A > 0
c) A = 1 et B = 5 -> croissant car A > 0
d) A = 1 et B = 0 -> croissant car A > 0
e) A = -1 et B = 0 -> décroissant car A < 0
f) A = 0 et B = 6 constante en 6 car A = 0
