bjr
A = 2/3 + (1/5)x 4 + 8/15 (la multiplication en premier)
= 2/3 + 4/5 + 8/15 (dénominateur commun 15)
= (2 x 5)/(3 x 5) + (4 x 3)/ (5 x 3) + 8/15
= 10/15 + 12/15 + 8/15
= (10 + 12 + 8)/15
= 30/15
= 2
B = 2/5 - (6/5)(2 + 3/4) ( ) d'abord
= 2/5 - (6/5) (8/4 + 3/4)
= 2/5 - (6/5) (11/4) ( produit en second)
= 2/5 - [(6 x 11)/(5 x 4)]
= 2/5 - [(3 x 11)/(5 x 2)] (on simplifie par 2)
= 2/5 - (33/10) (dénominateur commun 10)
= 4/10 - 33/10
= (4 - 33)/10
= - 29/10 ( ou -2,9)
