Réponse :
Explications étape par étape :
Bonsoir,
a) =A^2BAB = A^2A^3B = A^5B^2 = A^4AA^2 = IA^3 = A^3
b) = A^2BA^3B = A^2BAAB = A^2A^3BAAB = A^4AA^3BAB = I IA^3BB A^3A^2 = A^4A = IA = A
