Ответ:
3.
1) 23*7/36*7 + 31*4/63*4 = 161/252 + 124/252 = 285/252 = 95/84
2) 3*21/4*21 + 5*4/21*4 = 63/84 + 20/84 = 83/84
3) 95/84 – 83/84 = 12/84 = 1/7
4) 1/7 * 48 = 48/7
5) 3/5 : 7/8 = 3/5 * 8/7 = 24/35
6) 48/7 : 24/35 = 48/7 * 35/24 = 2 * 5 = 10 - числитель
7) 19*3/26*3 + 14*2/39*2 – 1*13/6*13 = 57/78 + 28/78 – 13/78 = 72/78 = 12/13
8) 12/13 * 54 1/6 = 12/13 * 325/6 = 2 * 25 = 50
9) 60/7 : 12/35 = 60/7 * 35/12 = 5*5 = 25
10) 50:25 = 2 – знаменатель
11) 10/2 = 5 – ответ
4.
1) 6 * 5/3 – 7/6 * 6/7 = 10 – 1 = 9
2) 21/5 * 10/11 + 57/11 = 42/11 + 57/11 = 99/11 = 9
3) 9 : 9 = 1 – первая дробь в квадратных скобках
4) (9/60 + 30/60 – 4/60) * 12/49 = 35/60 * 12/49 = 7/12 * 12/49 = 1/7
5) 10/3 + 2/9 = 30/9 + 2/9 = 32/9
6) 1/7 : 32/9 = 1/7 * 9/32 = 9/224 – вторая дробь в квадратных скобках
7) 1 – 9/224 = 215/224
8) 215/224 * 7/3 = 215/96
9) 13/4 – 215/96 = 13*24/4*24 – 215/96 = 312/96 – 215/96 = 97/96 = 1 1/96 - ответ