bonjour je suis en 3 eme qui pourrais m'aider svp d'avance merci

A = 4/3 - 5/3*-4/7
A = 4/3 + 20/21
A = (7*4)/(7*3) + 20/21
A = 28/21 + 20/21
A = 48/21

B = (1/2 - 1/4) / (7/8 - 4/5)

B = ((2*1)/(2*2) - 1/4) / ((7*5)/(8*5) - (4*8)/(5*8))

B = (2/4 - 1/4) / (35/40 - 32/40)

B = (1/4) / (3/40)

B = (1/4)*(40/3)

B = 40/12

B = (4*10)/(3*4) = 10/3

bonjour


A = 4/3 + 20/21 = 28/21 + 20/21 = 48/21 = 16/7

B = ( 1/2 - 1/4) : ( 7/8 - 4/5)

= ( 2/4 - 1/4) : ( 35/40 - 32/40) 

= 1/4 : 3/40 = 1/4 x 40/3 = 40/12  = 10/3