Réponse :
Explications étape par étape
a.
- si x*y = 6/5 * 2/3 = 12/15 = 4/5
- si x:y = 6/5 : 2/3 = 6/5 * 3/2 = 18/10 = 9/5
- si 1/x * 1/y = 1/6/5 * 1/2/3 = 1*5/6 * 1*3/2 = 5/6 * 3/2 = 15/12 = 5/4
b.
- si x*y = 7/9 * 7/9 = 49/81
- si x:y = 7/9 : 7/9 = 7/9 * 9/7 = 63/63 = 1
- si 1/x * 1/y = 1/7/9 * 1/7/9 = 1*9/7 * 1*9/7 = 9/7 * 9/7 = 81/49
