Bonsoir,
3/4 - 1/15 - 7/20
Déjà 3/4 -7/20 ( ce sera plus facile ensuite)
= 15/20 -7/20 = 8/20 = 4/10 = 2/5
2/5 - 1/15 = 6/15 - 1/15 = 5/15 = 1/3
Bonjour !
= (3*15)/(4*15) - (1*4)/(15*4) - (7*3)/(20*3)
= 45/60 - 4/60 - 21/60
= (45 - 4 - 21) / 60
= 20/60
= 1/3
J'espère t'avoir aidé. Bon courage !
