Bonjour
A = (3/2 - 1/3) : (3/4 + 2/3)
A = [(3 x 3) / (2 x 3) - (1 x 2) / (3 x 2)] : [(3 x 3) / (4 x 3) + (2 x 4) / (3 x 4)]
A = (9/6 - 2/6) : (9/12 + 8/12)
A = 7/6 : 17/12
A = 7/6 x 12/17
A = 84/102
A = (6 x 14) / (6 x 17)
A = 14/17
B = 7/5 + 8/15 : 2/3 - 19/2
B = 7/5 + 8/15 x 3/2 - 19/2
B = 7/5 + 24/30 - 19/2
B = (7 x 6) / (5 x 6) + 24/30 - (19 x 15) / (2 x 15)
B = 42/30 + 24/30 - 285/30
B = - 219/30
B = (3 x - 73) / (3 x 10)
B = - 73/10.