Cocou exercise 3 svp merci d'avance

A = - 7/3 + 8/15
A = - 7 x 5 / 3 x 5 + 8/15
A = - 35/15 + 8/15
A = - 27/15
A = 3 x - 9 / 3 x 5
A = - 9/5

B = - 7 - 1/4
B = - 7 x 4 / 1 x 4 - 1/4
B = - 28/4 - 1/4
B = - 29/4

D = 3/8 - 5/7
D = 3 x 7 / 8 x 7 - 5 x 8 / 7 x 8
D = 21/56 - 40/56
D = - 19/56

On ne voit ni le C ni le E