Explications étape par étape:
1) x = 7/3. x = 0
2) x = -5. x = 0
3) x = 2. x = 1 /8
4) x = 3/5 x = - 3/5
5) x = 3. x = - 11
6) x = - 1. x = 1
7) x = 1/4. x = 1
8) x = 11/7. x = 3/2
