Bonjour besoin d'aide 1/3-9/5 / 3+7/5

bonjour

1/3 -9/5 : 3+7/5
5/15 -27/15 :  45/15+7/15
-22/15 : 52/15
-22/15 x 15/52
-22/52
-11/26

Bonsoir,

1/3 - 9/5
 3 + 7/5
= 1 x 5 / 3 x 5 - 9 x 3 / 5 x 3
         3 x 5 / 1 x 5 + 7/5
= 5/15 - 27/15
   15/5 + 7/5
= - 22/15 : 22/5
= - 22/15 x 5/22
= - 110/330
= 10 x - 11 / 10 x 33
= - 11/33