Réponse :
Explications étape par étape :
a.2/7+3/14-1/21
a = 4/14 + 3/14 - 1/21
a = 7/14 - 1/21
a = 21/42 - 2/42
a = 19/42
b.5/6-19/3+7/18
b = 5/6 - 38/6 + 7/18
b = -33/6 + 7/18
b = -99/18 + 7/18
b = -92/18
b = -46/9
c.7/4+1/16-9/2
c = 28/16 + 1/16 - 72/16
c = 28/16 + 1/16 - 72/16
c = - 43/16
Bonne journée