Je ne comprends vraiment rien Exo1 et 2 Aider moi svp

Bonjour,

1)

a = 5/4 et b = - 8/3

S = a + b

S = 5/4 - 8/3

S = (5 x 3) / (4 x 3) - (8 x 4) / (3 x 4)

S = 15/12 - 32/12

S = - 7/12

D = a - b

D = 5/4 - (- 8/3)

D = 5/4 + 8/3

D = 15/12 + 32/12

D = 47/12

P = a x b

P = 5/4 x - 8/3

P = - 40/12

P = (4 x - 10) / (4 x 3)

P = - 10/3

Q = a : b

Q = 5/4 : - 8/3

Q = 5/4 x - 3/8

Q = - 15/32

2)

- - 7/5 = 7/5 = - 7/- 5 = - 7/- 5 = 1 : 5/7.

et

- 7/5 = 7/- 5 = - 7/5