Bonjour,
5x+2y=50
3x+7y=88
- 15x - 6y = - 150 (on multiplie par - 3)
15x + 35y = 440 (on multiplie par 5)
- 6y + 35y = 440 - 150
29y = 290
y = 290/29
y = 10
5x + 2y = 50
5x + 2 * 10 = 50
5x + 20 = 50
5x = 50 - 20
5x = 30
x = 30/5
x = 6
S = (6 ; 10)
Vérification :
5x + 2y = 50
5 * 6 + 2 * 10 = 50
30 + 20 = 50
50 = 50
et
3x + 7y = 88
3 * 6 + 7 * 10 = 88
18 + 70 = 88
88 = 88.