Réponse :
Explications étape par étape
Bonjour
(5/7 - 2)/(5/3 - 4/7)
= [5/7 - (2 x 7)/7] / [(5 x 7)/(3 x 7) - (4 x 3)/(7 x 3)]
= (5/7 - 14/7) / (35/21 - 12/21)
= (-9/7) / (23/21)
= (-9/7) x 21/23
= -21/7 x 9/23
= (-3 x 7)/7 x 9/23
= -3 x 9/23
= -27/23