bonsoir
a = 6 a /5
b = 2 b /3 + 1/3
c = 3 c + 12/14 + 7/14 = 3 c + 19/14
d = 4 y x 7/2 = 28 y / 2 = 14 y
e = x /5 + 5 x /4 = 4 x /20 + 25 x /20 = 29 x /20
f = 12 n / 15 = 4 n /5