Ответ:
1) 3 11/12
2) 27/64
Пошаговое объяснение:
6 - 1 9/12 * 3 + 3/6 * 7/21 = 3 11/12
1) 1 9/12 * 3/1 = 9/4 = 2 1/4
2) 3/6 * 7/21 = 1/6 * 7/7 = 1/6
3) 6 - 2 1/4 = 5 4/4 - 2 1/4 = 3 3/4
4) 3 3/4 + 1/6 = 3 9/12 + 2/12 = 3 11/12
__________________________________
(3/4)³ = 3* 3 * 3 / 4 * 4 * 4= 27/64