Bonjour
Il faut trouver la fraction irreductible egale a chacune des expressions suivantes
1/3 - 1 - 8/3
= 1/3 - 3/3 - 8/3
= (1 - 3 - 8)/3
= (1 - 11)/3
= -10/3
14/21 - 30/150 - 12/27
= (2 x 7)/(3 x 7) - 30/(30 x 5) - (3 x 4)/(3 x 9)
= 2/3 - 1/5 - 4/9
= (2 x 15)/(3 x 15) - (1 x 9)/(5 x 9) - (4 x 5)/(9 x 5)
= 30/45 - 9/45 - 20/45
= (30 - 9 - 20)/45
= (30 - 29)/45
= 1/45
7/12 + 15/25 - 11/44
= 7/12 + (5 x 3)/(5 x 5) - 11/(4 x 11)
= 7/12 + 3/5 - 1/4
= (7 x 5)/(12 x 5) + (3 x 12)/(5 x 12) - (1 x 15)/(4 x 15)
= 35/60 + 36/60 - 15/60
= (35 + 36 - 15)/60
= (71 - 15)/60
= 56/60
= (4 x 14)/(4 x 15)
= 14/15
