exercice 5 aidez moi svpppp

- 5a + 3b = - 3
2a + b = 10

1)
2a + b = 10
b = 10 - 2a

2)
b = 10 - 2a

- 5a + 3b = - 3
- 5a + 3(10 - 2a) = - 3
- 5a + 30 - 6a = - 3
30 + 3 = 6a + 5a
33 = 11a
33/11 = a
3 = a

b = 10 - 2a
b = 10 - 2 x 3
b = 10 - 6
b = 4