Вычислите а) (1/2: 3/4-4/9): 3/5 b) 1/2: 3/8-4/9: 3/5

(1/2 : 3/4 - 4/9) :3/5= (1/2 х 4/3 - 4/9): 3/5= (2/3 - 4/9): 3/5= (6/9-4/9): 3/5=
= 2/9 :3/5= 2/9 х 5/3= 10/27
1/2 : 3/8 - 4/9 : 3/5= 1/2 х 8/3 - 4/9 х 5/3= 4/3 - 20/27= 36/27 - 20/27= 16/27