Bonjour
Y = 4/9 + 8/15 - 2/3
Y = (4 x 10) / (9 x 10) + (8 x 6) / (15 x 6) - (2 x 30) / (3 x 30)
Y = 40/90 + 48/90 - 60/90
Y = 28/90
Y = (2 x 14) / (2 x 45)
Y = 14/45
Z = 1/6 - 8/27 - 7/18
Z = (1 x 9) / (6 x 9) - (8 x 2) /(27 x 2) - (7 x 3) / (18 x 3)
Z = 9/54 - 16/54 - 21/54
Z = - 28/54
Z = (2 x - 14) / (2 x 27)
Z = - 14/27.
