Réponses

2014-09-14T16:48:01+02:00
Bonjour

a) 1/2 + 2/3 = 3/6 + 4/6 = 7/6

b) 19/20 - 4/5 = 19/20 - 16/20 = 3/20

c) -2/7 : 5/2 = -2/7 x 2/5 = - 4/35

d) (2/5 x 3/4 ) - (6/5 x 7/4) = 6/20 - 42/20 = - 36/20 ou - 9/5
explique moi ton resonement stp
dsl maos expliqur moi ton resonement
il n'y a pas de raisonnement, ce sont des calculs, c'est tout
ok
2014-09-14T16:56:27+02:00
A) 1/2 + 2/3
= 1*3/2*3 +2*2/3*2
= 3/6 +4/6
= 7/6

b) 19/20 -4/5
= 19/20 -4*4/5*4
= 19/20 -16/20
= 3/20

c) -2/7: 5/2
= -2/7*2/5
= -4/35

d) 2/5*3/4 -6/5*7/4
= 2*3/5*2*2 -3*2*7/5*2*2
= 3/10 -21/10
= -18/10
= -9*2/5*2
= -9/5