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

3/5:(1/2:3/4-4/9):3/5= 3/5 / (1/2* 4/3 - 4/9) / 3/5 = 4/6 - 4/9 = 12/18- 8/18 = 4/18 = 2 /9 3/5:9/10-3/5*8/9 =3/5 * 10/9 - 3/5 * 8/9 = 30/45 - 24/45 = 6/45