Réponse :

Explications étape par étape :

Bonsoir

(1 + 1/2) × 5 -  3/4 = 3/2 × 5 - 3/4 = 15/2 - 3/4 = 30/4 - 3/4 = 27/4

1 + 1/2 ×( 5 -  3/4 ) = 1 + 1/2 ×( 20/4 -  3/4 ) = 1 + 1/2 ×( 17/4 ) = 1 + 17/8 = 8/8 + 17/8 = 25/8

4 - 1/9 × 3 + 1/3 = 4 - 3/9 + 1/3 = 4 - 1/3 + 1/3 = 4

(2/7 + 5/3) /( 10/3) - 4/7 = [(6 +15)/21] × 3/10 - 4/7 = (21/21) × 3/10 - 4/7= 1 × 3/10 - 4/7 = 3/10 - 4/7 = (21 - 40)/ 70 = ( -19) /70