Bonsoir,
A = 3/4 + 8/5
A = (3 x 5) / (4 x 5) + (8 x 4) / (5 x 4)
A = 15/20 + 32/20
A = 47/20
B = 3/4 - 9/7
B = (3 x 7) / (4 x 7) - (9 x 4) / (7 x 4)
B = 21/28 - 36/28
B = - 15/28
C = 7/3 x - 5/6
C = - 35/18
D = 21/- 25 x - 10/49
D = 210/1 225
D = (35 x 6) / (35 x 35)
D = 6/35.
