Bonsoir,
Exercice 1 :
15/21 = 15 ÷ 3 / 21 ÷ 3 = 5/7
10/14 = 10 ÷ 2 / 14 ÷ 2 = 5/7
30/48 = 30 ÷ 6 / 48 ÷ 6 = 5/8
3/21 = 3 ÷ 3 / 21 ÷ 3 = 1/7
40/75 = 40 ÷ 5 / 75 ÷ 5 = 8/15
34/28 = 34 ÷ 2 / 28 ÷ 2 = 17/14
Exercice 2 :
a) x = 4/7
7 × 4/7 = 4
b) x = 8/6 = 4/3
4/3 × 6 = 8
c) x = 33/15 = 11/5
15 × 11/5 = 33
d) x = 7/12
12 × 7/12 = 7
