Le F , G et H svp je comprend pas

bonsoir

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

F = (9/3 - 2/3) / (28/3)

F = 7/3 x 3/28

F = 7/28 x 3/3

F = 7/(7 * 4)

F = 1/4

G = (2/3) / (5/6) - 2/5

G = 2/3 x 6/5 - 2/5

G = 6/3 x 2/5 - 2/5

G = (2 x 3)/3 x 2/5 - 2/5

G = 2 x 2/5 - 2/5

G = 4/5 - 2/5

G = 2/5

H = (-3/4 + 1/2)/(2/5 - 5/2)

H = (-3/4 + 2/4) / (4/10 - 25/10)

H = (-1/4) / (-21/10)

H = 1/4 x 10/21

H = 10/4 x 1/21

H = (2 x 5)/(2 x 2) x 1/21

H = 5/2 x 1/21

H = 5/42