Bonjour, Pouvez vous m'aider pour mon exercice de maths, S'il vous plait?

a = 7/5 -7/3x1514
a =7/5 -5/2
a = 14/10 -25/10
a = -11/10

b = 8/5 -3/4 :9/8
b = 8/5 -3/4x8/9
b = 8/5 -2/3
b = 24/15 -10/15
b =14/15

c = 8/3-2/5  / 7/5
c = (40/15 -6/15 )x 5/7
c = 34/15 x 5/7
c = 34/3x1/7
c =34/21

1)
a) = 18
b) = ( -13) 
c) = 17,4
d) = 1,2