bonsoir
13 a + 11 b + 75 = 13.6 a + 13.6 b + 68
13 a - 13.6 a + 11 b - 13.6 b = 68 - 75
- 0.6 a - 2.6 b = - 7
15 a + 17 b + 70 = 14.9 a + 14.9 b + 74.5
15 a- 14.9 a + 17 b - 14.9 b = 74. 5 - 70
0.1 a + 2.1 b = 4.5
- 0.6 a - 2.6 b = - 7
0.1 a + 2.1 b = 4.5
- 0.6 a - 2.6 b = - 7
0.6 a + 12.6 b = 27
10 b = 20
b = 2
- 0.6 a - 5.2 = - 7
- 0.6 a = - 7+ 5.2
- 0.6 a = 1.8
a = 3