Réponse :
bonjour
A = - 4/15 + 7/2
= - 8/30 + 105/30
= 97/30
B = 7/3 - 30/42
= 7/3 - 5/7
= 49/21 - 15/21
= 34/21
C = 12/5 + 21/45
= 12/ 5 + 7/15
= 36/15 + 7/15 = 43/15
*D = - 2/3 ( 16/20 + 3 /20 )
= - 2/3 x 19/20
= - 38/60 = - 19/30
Explications étape par étape :
