Exercice 1,2,3,4 merci svp c pour demain un dm de math

Réponse :

Bonjour

Explications étape par étape

Exercice 1

2/15 + 7/5 = 2/15 + 7/5 X 3/3 = 14/15 +21/15 = 35/15 : 5/5 = 7/3

5/7 -31/21 = 5/7 X 3/3 -31/21 = 15/21 -31/21 = -16/21

3/7 +2/5 = 3/7 X 5/5 +2/5 X 7/7 = 15/35 +14/35 = 29/35

7/18 -1/12 = 7/18 X 12/12 -1/12 X 18/18 = 84/216 -18/216 = 66/216 : 3/3 = 22/72

= 11/36

Exercice 2

7/3 X 2/9 = 14/27

3/7 X 5/11 = 15/77

15/8 X 6/25 = 90/200 = 9/20

21/20 X 15/14 = 315/280 : 5/5 = 63/56 : 7/7 = 9/7