Salut je suis en 4eme et je comprend pas l'exercice, quelqun pourrai maide svp je vous en suplu​

Bonsoir,

1)

21/14 = (7 x 3) / (7 x 2) = 3/2

24/- 22 = (2 x - 12) / (2 x 11) = - 12/11

- - 25/55 = (5 x 5) / (5 x 11) = 5/11

- 24/- 30 = (6 x 4) / (6 x 5) = 4/5.

2)

- 2/7 + 9/7 = 7/7 = 1

2/- 9 + - 8/9 = - 10/9

- 17/- 36 - - 5/- 9

= 17/36 - (5 x 4) / (9 x 4)

= 17/36 - 20/36

= - 3/36

= (3 x - 1) / (3 x 13)

= - 1/13.

18/7 - 11/5

= (18 x 5) / (7 x 5) - (11 x 7) / (5 x 7)

= 90/35 - 77/35

= 13/35

1/5 - - 11/25 + 21/100

= (1 x 20) / (5 x 20) + (11 x 4) / (25 x 4) + 21/100

= 20/100 + 44/100 + 21/100

= 65/100

= (5 x 13) / (5 x 20)

= 13/20.