Pouvez me calculez ces calcul en détaillant

A = - 5/6 + 13/4
A = - 5 x 4 / 6 x 4 + 13 x 6 / 4 x 6
A = - 20/24 + 78/24
A = 58/24
A = 2 x 29 / 2 x 12
A = 29/12

B = 8/7 : - 8/5
B = 8/7 x - 5/8
B = - 40/56
B = 8 x - 5 / 8 x 7
B = - 5/7

C = 2/5 + - 3/8 x 12/-5
C = 2/5 - 3/8 x - 12/5
C = 2/5 + 26/40
C = 2 x 8 / 5 x 8 + 36/40
C = 16/40 + 36/40
C = 52/40
C = 4 x 13 / 4 x 10
C = 13/10

D = (- 5/7 + 1/5) :  (- 4/7 + 2)
D = (- 5 x 5 / 7 x 5 + 1 x 7 / 5 x 7) : (- 4 /7 + 2 x 7 / 1 x 7)
D = (- 25/35 + 7/35) : (- 4/7 + 14/7)
D = - 18/35 : 10/7
D = - 18/35 x 7/10
D = - 126/350
D = 14 x - 9 / 14 x 25
D = - 9/25
 

A = - 5/6 + 13/4
= - 5 x 4 / 6 x 4 + 13 x 6 / 4 x 6
= - 20/24 + 78/24
= 58/24
= 2 x 29 / 2 x 12
= 29/12

B = 8/7 : - 8/5
= 8/7 x - 5/8
= - 40/56
= 8 x - 5 / 8 x 7
= - 5/7

C = 2/5 + - 3/8 x 12/-5
= 2/5 - 3/8 x - 12/5
= 2/5 + 26/40
= 2 x 8 / 5 x 8 + 36/40
= 16/40 + 36/40
= 52/40
= 4 x 13 / 4 x 10
= 13/10

D = (- 5/7 + 1/5) :  (- 4/7 + 2)
 = (- 5 x 5 / 7 x 5 + 1 x 7 / 5 x 7) : (- 4 /7 + 2 x 7 / 1 x 7)
= (- 25/35 + 7/35) : (- 4/7 + 14/7)
 = - 18/35 : 10/7
= - 18/35 x 7/10
= - 126/350
= 14 x - 9 / 14 x 25
= - 9/25