Bonjour
A = 8/7 - - 4/7 x 5/3
A = 8/7 - - 20/21
A = (8 x 3) / (7 x 3) + 20/21
A = 24/21 + 20/21
A = 44/21
B = - 3 : (2 + 5/2)
B = - 3 : [(2 x 2) / (1 x 2) + 5/2]
B = - 3 : (4/2 + 5/2)
B = - 3 : 9/2
B = - 3 x 2/9
B = - 6/9
B = (3 x - 2) / (3 x 3)
B = - 2/3
C = (- 2/3 - - 4/9) : (5/2 + 1/2 x 3/- 7)
C = [(-2 x 3) / (3x 3)] + 4/9] : (5/2 - 3/14)
C = (- 6/9 + 4/9) : [(5 x 7) / (2 x 7) - 3/14]
C = - 2/9 : (35/14 - 3/14)
C = - 2/9 : 32/14
C = - 2/9 x 14/32
C = - 28/288
C = (4 x - 7) / (4 x 72)
C = - 7/72.
