Répondre :
A)3/4 = 6/8
donc 6/8 + 5/8 = 11/8
B) 7/15 - 12/25 = 35/75 - 36/75
= -1/75
C) -12/-7 x -9/49 = 108/-343
D) 3/7 + 4/7 + 14/3 = 9/21 + 12/21 + 98/21 = 119/21
donc 6/8 + 5/8 = 11/8
B) 7/15 - 12/25 = 35/75 - 36/75
= -1/75
C) -12/-7 x -9/49 = 108/-343
D) 3/7 + 4/7 + 14/3 = 9/21 + 12/21 + 98/21 = 119/21