Aidez moi je suis perdue. Merci d'avance.

bonjour

b = 15/14 - 12/21
b = 45/42 - 24/42
b = 21/42 = 1/2

c = 3 + 5/4 x ( 10/5 - 1/5)
c = 3 + 5/4 x 9/5
c= 3 + 45/20
c = 60/20  +45/20
c = 105/20 = 21/5

d = 25/14 x 14/15 - 11/3
d = 350/255 - 11/3
d = 350/255 - 935/255
d = - 585/255 = - 39/17

e = 5/4 - 18/48
e = 60/48 - 18/48
e = 42/48
e = 7/8

f = 1/3 + 14/3 x 12/35
f = 1/3 + 168/105
f = 35/105 + 168/105
f = 203/105 = 29/15