Dm pour demain svp aider moi

A = 2/3 + - 4/3 x 2/7
A = 2/3 - 4/3 x 2/7
A = 2/3 - 8/21
A = 2 x 7 / 3 x 7 - 8/21
A = 14/21 - 8/21
A = 6/21
A = 3 x 2 / 3 x 7
A = 2/7

B = (1/3 - 1/7) : 2/7
B = (1 x 7 / 3 x 7 - 1 x 3 / 7 x 3) : 2/7
B = (7/21 - 3/21) : 2/7
B = 4/21 : 2/7
B = 4/21 x 7/2
B = 28/42
B = 14 x 2 / 14 x 3
B = 2/3