Réponses

2014-05-22T20:59:28+02:00
Bonsoir

soit x le chocolat et y le café

x + y = 5.5
4x + 2y = 17

- 2x -2y = - 11
4x +2y = 17
2x = 6
x = 3

le chocolat = 3 €

x +y = 5.5
3 +y = 5.5
y = 5.5 -3
y = 2.5
le café = 2.5€

4x +2 y = 17
12 + 5 = 17