4. 1 3 2 4
а) (1 17/25 * 2 1/7 - 2 4/7 * 1 2/5) * 2 7/9 = 0
1) 1 17/25 * 2 1/7 = 42/25 * 15/7 = 6 * 3 / 5 * 1 = 18/5
2) 2 4/7 * 1 2/5 = 18/7 * 7/5 = 18/5
3) 18/5 - 18/5 = 0
4) 0 * 2 7/9 = 0
4 1 2 3
б) 1/2 + (5 1/6 - 3 3/4 + 1/2) * 10/23 = 1 1/3
1) 5 1/6 - 3 3/4 = 31/6 - 15/4 = 62/12 - 45/12 = 17/12
2) 17/12 + 1/2 = 17/12 + 6/12 = 23/12
3) 23/12 * 10/23 = 10/12
4) 10/12 + 1/2 = 10/12 + 6/12 = 16/12 = 1 4/12 = 1 1/3
5. а) 2/7а + 5/14а - 20/21а = 12/42а + 15/42а - 40/42а = - 13/42а
б) 3 2/3n - 2 4/9n + 1 1/2n = 11/3n - 22/9n + 3/2n = 66/18n - 44/18n + 27/18n =
= 49/18n = 2 13/18n