Вычислите: (1/2:3/4-4/9):3/5 1/2:3/8-4/9:3/5 3/5:(9/10-3/5*8/9 3/5:9/10-3/5*8/9

1) (1/2 : 3/4 - 4/9) : 3/5 = (1/2 * 4/3 - 4/9) : 3/5 = (6/9 - 4/9) * 5/3 = 3/9 * 5/3 = 5/9;

2) 1/2 : 3/8 - 4/9 : 3/5 = 1/2 * 8/3 - 4/9 * 5/3 = 4/3 - 20/27 = 36/27 - 20/27 = 16/27;

3) 3/5 : (9/10 - 3/5 * 8/9) = 3/5 : (9/10 - 24/45) = 3/5 : (81/90 - 48/90) = 3/5 : 33/90 = 3/5 * 90/33 = 90/55 = 18/11;

4) 3/5 : 9/10 - 3/5 * 8/9 = 3/5 * 10/9 - 3/5 * 8/9 = 30/45 - 24/45 = 6/45 = 2/15.