Bonjour
A = 2/5 - 4/5 x 2 /3
= 2/5 - 8/15
= 6/15 - 8 /15
= - 2 /15
C = ( 8/3 - 2/5 ) : 7/5
= ( 40/15 - 6/15 ) ; 7/5
= 34 /15 x 5/7
= 510/105
= 34/ 7
B = ( 7 - 1/4 ) : 3/2
= ( 28/4 - 1/4 ) : 3/2
= 27/4 x 2/3
= 54 / 12 = 9/2
allez fais le dernier tu mets sous 15