помогите решить примеры с дробями. 1) (12/7 - 20/21)*56/16. 2) (8/11- 20/55)*66/20. 3) (7/6 - 1/12 + 1/36) * 72/34. 4) (8/7 - 1/14 +1/42)*12/46​

Ответ:

Пошаговое объяснение:

1) (12/7 - 20/21)*56/16 =  2 2/3

          1) 12/7 - 20/21 = 36/21 - 20/21 = 16/21

          2) 16/21 * 56/16 = 1/3 * 8/1 = 8/3 = 2 2/3

2) (8/11- 20/55)*66/20 = 1 1/5

           1) 8/11 - 20/55 = 40/55 - 20/55 = 20/55 = 4/11

           2) 4/11 * 66/20 = 6/5 = 1 1/5

3) (7/6 - 1/12 + 1/36) * 72/34 = 2 6/17

             1) 7/6 - 1/12 = 14/12 - 1/12 = 13/12

             2) 13/12 + 1/36 = 39/36 + 1/36 = 40/36 = 10/9

             3) 10/9 * 72/34 = 5/1 * 8/17 = 40/17 = 2 6/17

4) (8/7 - 1/14 +1/42)*12/46​ = 2/7

                1) 8/7 - 1/14 = 16/14 - 1/14 = 15/14

                2) 15/14 + 1/42 = 45/42 + 1/42 = 46/42

                 3) 46/42 * 12/46 = 12/42 = 2/7