A= 3a + 5 - (2a+7) + (8-5a)
3a + 5 - 2a - 7 + 8 - 5a = -4a + 6
B= -b + 4 + (3b-2) - (8b-5)
-b + 4 + 3b - 2 - 8b + 5 = -6b + 7
C= 6 - 5c + 3c - (4-6c) + 5 + (7-2c)
6 - 5c + 3c - 4 + 6c + 5 + 7 - 2c = 2c +14
D= d - 1 - (3d+4) + (5-4d) - (7d+5) + 5
d - 1 - 3d - 4 + 5 - 4d - 7d - 5 + 5 = -13d
Voila, bon courage
