svp aider moi c pour demain

Bonjour

A = 1 - 5/9
A = 1 x 9 / 1 x 9 - 5/9
A = 9/9 - 5/9
A = 4/9

B = - 4 + 7/3
B = - 4 x 3 / 1 x 3 + 7/3
B = - 12/3 + 7/3
B = - 5/3

C = 5/4 - 7
C = 5/4 - 7 x 4 / 1 x 4
C = 5/4 - 28/4
C = - 23/4

D = - 7 - 4/3
D = - 7 x 3 / 1 x 3 - 4/3
D = - 21/3 - 4/3
D = - 25/3