Bonjour,
A = 35/12 x 18/15
A = 630/180
A = (90 x 7) / (90 x 2)
A = 7/2
B = - 56/24 x 36/63
B = - 2 016/1 512
B = (504 x - 4) / (504 x 3)
B = - 4/3
C = - 4 x 5/8
C = - 20/8
C = (4 x - 5) / (4 x 2)
C = - 5/2
D = - 21/18 x 24/- 15
D = 504/270
D = (18 x 28) / (18 x 15)
D = 28/15.