Svp, je n'y arrives ! Merci d'avance !!!

Bonsoir

E = (-7 / 5) / (6 + 1 / 5)
= (-7 / 5) / [ (6 x 5) / (1 x 5) + 1 / 5 ]
= (-7 / 5) / (30 / 5 + 1 / 5)
= (-7 / 5) / (31 / 5)
= (-7 / 5) x (5 / 31)
= (-7 x 5) / (5 x 31)
= -7 / 31

F = (3 / 4) / (7 / 8) - 3 / 7
= (3 / 4) x (8 / 7) - 3 / 7
= (3 x 8) / (4 x 7) - 3 / 7
= (3 x 4 x 2) / (4 x 7) - 3 / 7
= 6 / 7 - 3 / 7
= 3 / 7

G = (3 / 2 - 1 / 4) / (2 - 1 / 2)
= [(3 x 2) / (2 x 2) - 1 / 4] / [(2 x 2) / (1 x 2) - 1 / 2]
= (6 / 4 - 1 / 4) / (4 / 2 - 1 / 2)
= (5 / 4) / (3 / 2)
= (5 / 4) x (2 / 3)
= (5 x 2) / (4 x 3)
= (5 x 2) / (2 x 2 x 3)
= 5 / 6

Voilà j'espère avoir pu t'aider ^^