5/6-25/49:(3-1 13/14) + 1/2 = 6/7

1) 3 - 1 13/14 = 1 1/142) 25/49 : 1 1/14 = 25/49 * 14/15 = 10/213) 5/6 - 10/21 = 70/84 - 40/84 = 30/84 = 5/144) 5/14 + 1/2 = 5/14 + 7/14 = 12/14 = 6/7ответ: 6/7