Bonjour
A = 4/5 - 7/5 x 10/4
A = 4/5 - 70/20
A = (4 x 4) / (5 x 4) - 70/20
A = 16/20 - 70/20
A = - 54/20
A = (2 x - 27) / (2 x 10)
A = - 27/10
B = 6/5 - 17/14 : 5/7
B = 6/5 - 17/14 x 7/5
B = (6 x 14) / (5 x 14) - 119/70
B = 84/70 - 119/70
B = - 35/70
B = (35 x - 1) / (35 x 2)
B = - 1/2.
