Répondre :
1)
A = 1 - (2/3 + 1/4) = 1 - (8/12 + 3/12) = 1 - 11/12 = 12/12 - 11/12 = 1/12
B = 3 - 5/2 = 6/2 - 5/2 = 1/2 = 1/2 * 5/6 = 5/12
1 + 1/5 5/5 + 1/5 6/5
2)
C = 4/5 * 35/8 = 140/40 = 7/2
3) 1/12 + 5/12 + 7/2 = 1/12 + 5/12 + 42/12 = 48/12 = 4
A = 1 - (2/3 + 1/4) = 1 - (8/12 + 3/12) = 1 - 11/12 = 12/12 - 11/12 = 1/12
B = 3 - 5/2 = 6/2 - 5/2 = 1/2 = 1/2 * 5/6 = 5/12
1 + 1/5 5/5 + 1/5 6/5
2)
C = 4/5 * 35/8 = 140/40 = 7/2
3) 1/12 + 5/12 + 7/2 = 1/12 + 5/12 + 42/12 = 48/12 = 4