Voici la question d'un DM de maths : (voir photo) merci de m'aider :-)

A= 3/4 - 5/4 x 1/2

A= 3/4 - 5/8

A= 3x2 / 4x2 - 5/8

A= 6/8 - 5/8

A= 1/8

B= 7/15 - 2/15 x 9/4

B= 7/15 - 18/60

B= 7x4 / 15x4 - 18/60

B= 28/60 - 18/60

B= 10/60

B= 1x10 / 6x10

B= 1/6

C= 6/5 - 17/14 : 5/7

C= 6/5 - 17/14 x 7/5

C= 6/5 - 17x7 / 7x2x5

C= 6/5 - 17/2x5

C= 6/5 - 17/10

C= 6x2 / 5x2 - 17/10

C= 12/10 - 17/10

C= -5/10

C= -1x5 / 2x5

C= -1/2

D= 3/4 + 5/4 : (4/3 - 1/2)

D= 3/4 + 5/4 : (4x2 / 3x2 - 1x3 / 2x3)

D= 3/4 + 5/4 : (8/6 - 3/6)

D= 3/4 + 5/4 : 5/6

D= 3/4 + 5/4 x 6/5

D= 3/4 + 30/20

D= 3x5 / 4x5 + 30/20

D= 15/20 + 30/20

D= 45/20

D= 9x5 / 4x5

D= 9/4