exercice 1 exercice 16
exercice 2 exercice 17
exercice 3 exercice 18
exercice 4 exercice 19
exercice 5 exercice 20
exercice 6
exercice 7
exercice 8
exercice 9
exercice 10
exercice 11
exercice 12
exercice 13
exercice 14
exercice 15