Réponses

2014-06-05T19:06:49+02:00
Bonsoir

3x -y = 11
x - 5y = 57

- y = 11 - 3x

x - 5(11 -3 x ) = 57
x - 55 + 15x = 57
14x = 57 + 55
14x = 112
x = 8

24 - y = 11
- y = 11 -24
- y = - 13
y = 13

On vérifie
x - 5y = 57
8 - 65 = 57
57 = 57