Réponses

2014-09-15T12:47:49+02:00
Exprimer sous forme de fraction irréductible :
4/5 - 2/3 : 1/4 - 2/3
= 4/5 - 2/3 x 4/1 - 2/3
= 4/5 - 8/3 - 2/3
= 4 x 3 / 5 x 3 - 8 x 5 / 3 x 5 - 2 x 5 / 3 x 5
= 12/15 - 40/15 - 10/15
= 12/15 - 50/15
= 38/15

15/8 x 2/21 x 49
= 30/168 x 49
= 1470/168
= 42 x 35 / 42 x 4
= 35/4


2014-09-15T15:44:57+02:00
4/5 - 2/3 : 1/4 - 2/3
= 4/5 - 2/3 x 4/1 - 2/3
= 4/5 - 8/3 - 2/3
= 4 x 3 / 5 x 3 - 8 x 5 / 3 x 5 - 2 x 5 / 3 x 5
= 12/15 - 40/15 - 10/15
= 12/15 - 50/15
= 38/15
15/8 x 2/21 x 49
= 30/168 x 49
= 1470/168
= 42 x 35 / 42 x 4
= 35/4