Пошаговое объяснение:
№1
1) 4. 1/5 : 7/15 = 21/5 : 7/15 = 21/5 * 15/7 = 3/1 * 3/1 = 9/1 = 9
2) 9 : 1/3 = 9 * 3/1 = 27/1 = 27
№2
1) 7/15 : 1/3 = 7/15 * 3/1 = 7/5 * 1/1 = 7/5
2) 4. 1/5 : 7/5 = 21/5 : 7/5 = 21/5 * 5/7 = 3/1 * 1/1 = 3/1 = 3
№3
1) 5. 8/9 : 1. 17/36 = 53/9 : 53/36 = 53/9 * 36/53 = 1/1 * 4/1 = 4/1 = 4
2) 4 + 1. 1/4 = 5. 1/4
3) 5. 1/4 : 4. 1/5 = 21/4 : 21/5 = 21/4 * 5/21 = 1/4 * 5/1 = 5/4 = 1. 1/4
№4
1) 2. 1/4 + 4. 5/6 = 2. 3/12 + 4. 10/12 = 6. 13/12 = 7. 1/12
2) 7. 1/12 : 3. 2/5 = 85/12 : 17/5 = 85/12 * 5/17 = 5/12 * 5/1 = 25/12 = 2. 1/12
3) 3/4 : 3/5 = 3/4 * 5/3 = 1/4 * 5/1 = 5/4 = 1. 1/4
4) 2. 1/12 - 1. 1/4 = 2. 1/12 - 1. 3/12 = 1. 13/12 - 1. 3/12 = 10/12 = 5/6
6) Аналогично, используя свойство модуля, получим, что |9 + x| = 0, откуда x = –9.
ответ: 4) 2; 6) –9.