Bonsoir,
A = 5/7 - 12/28 x 20/6
A = 5/7 - 240/168
A = 5/7 - (24 x 10) / (24 x 7)
A = 5/7 - 10/7
A = - 5/7
B = 27/18 - 1/2 - ( 1- 9/15)
B = 27/8 - 1/2 - [(1 x 15) / (1 x 15) - 9/15]
B = 27/8 - 1/2 - (15/15 - 9/15)
B = 27/8 - 1/2 - 6/15
B = 27/8 - 1/2 - (3 x 2) / (3 x 5)
B = 27/8 - 1/2 - 2/5
B = (27 x 5) / (8 x 5) - (1 x 20) / (2 x 20) - (2 x 8) / (5 x 8)
B = 135/40 - 20/40 - 16/40
B = 99/40
C=. 16/9 x 3/14 X 5/8
C = 48/126 x 5/8
C = 240/1 008
C = (48 x 5) / (48 x 21)
C = 5/21.
