Bonjour
E = 4/15 : 2/3 = 4/15 x 3/2 = 12/30 = (6 x 2) / (6 x 5) = 2/5
F = - 54/35 : 27/14 = - 54/35 x 14/27 = - 756/945 = (189 x - 4) / (189 x 5) = - 4/5
G = - 24/11 : (- 6) = - 24/11 x (- 1/6) = 24/66 = (6 x - 4) / (6 x 11) = - 4/11
H = 2/9 : 7/24 = 2/9 x 24/7 = 48/63 = (3 x 16) / (3 x 21) = 16/21
I = 7/8 : 1/- 4 = 7/8 x (- 4) = - 28/8 = (4 x - 7) / (4 x 2) = - 7/2
J = 10 : 3/2 = 10 x 2/3 = 20/3.