J’arrive pas le faire,c’est pour demain, vous pouvez m’aider ??

Bonjour

A = - 1/15 + 3/20

A = (- 1 x 4) / (15 x 4) + (3 x 3) / (20 x 3)

A = - 4/60 + 9/60

A = 5/60

A = (5 x 1) / (5 x 12)

A = 1/12

B = 4/7 + (- 1/15)

B = (4 x 15) / (7 x 15) - (1 x 7) / (15 x 7)

B = 60/105 - 7/105

B = 53/105

C = - 5/12 + 4/15

C = (- 5 x 5) / (12 x 5) + (4 x 4) / (15 x 4)

C = - 25/60 + 16/60

C = - 9/60

C = (3 x - 3) / (3 x 20)

C = - 3/20

D = - 2/15 - 3/10

D = (- 2 x 2) / (15 x 2) - (3 x 3) / (10 x 3)

D = - 4/30 - 9/30

D = - 13/30

E = - 11/20 + 7/12

E = (- 11 x 3) / (20x 3) + (7 x 5) / (12 x 5)

E = - 33/60 + 35/60

E = 2/60

E = (2 x 1) / (2 x 30)

E = 1/30

F = - 2/11 - 5/33

F = (- 2 x 3) / (11 x 3) - 5/33

F = - 6/33 - 5/33

F = - 11/33

F = (11 x - 1) / (11 x 3)

F = - 1/3