Réponse :
bonjour
A = ( 2/3 + 5/7 ) / ( 2/3 x 5/7 )
A = ( 14/21 + 15/21 ) / 10/21
A = 29/21 : 10/21
A = 29/21 x 21/10
A = 29/10 = 2.9
B = ( 5 + 3/4 - 1/3 ) : ( 5 - 3/4 + 1/3 )
B = ( 60 /12 + 9/12 - 4/12 ) : ( 60/12 - 9/12 + 4/12 )
B = 65/12 : 55/12
B = 65/12 x 12/55
B = 65/55 = 13/11
C = ( 1/5 - 3/4 x 2/3 ) : ( 1/5 - 3/4 ) x 2/3
C = ( 1/5 - 6/12 ) : ( 4/20 - 15/20 ) x 2/3
C = ( 12/60 - 30/60 ) : ( - 11/20 x 2/3 )
C = - 18/60 : - 22/60
C = - 18/60 x - 60/22
C = 18/22 = 9 /11
Explications étape par étape :
