Réponse :

bonjour

Explications étape par étape :

A= -8/9+7/4

= -32/36 +63/36  

= 31/36

B=11/3 – 5/4

=44/12 – 15/12

=29/12

C=-2/3-10/7

=-14/21 – 30/21

=-44/21

A=14/15-7/20-1/6

=56/60 -21/60-10/60

=25/60

=5/12

B= -5/8 + 5/24 +5/12

=-15/24 +5/24 +10/24

=0