Выполните действия (21/2) ²*8/15-5/9 б) (21/3*1 2/7) ³*2/9 в) (3 1/14-2 5/21) * (2,7-2,1)

1) (21/2) ^2 * 8/15 - 5/9 = 21^2/2^2 * 8/15 - 5/9 = 441/4 * 8/15 - 5/9 = (441 * 8) / (4 * 15) - 5/9 = (147 * 2) / 5 - 5/9 = 294/5 - 5/9 = 2646/45 - 25/45 = 2621/45;

2) (21/3 * 1 2/7) ^3 * 2/9 = (7 * 9/7) ^3 * 2/9 = 9^3 * 2/9 = (9 * 9 * 9 * 2) / 9 = 162;

3) (3 1/14 - 2 5/21) * (2,7 - 2,1) = ((3 * 14 + 1) / 14 - (2 * 21 + 5) / 21) * 0,6 = (43/14 - 47/21) * 6/10 = (129/42 - 94/42) * 6/10 = 35/42 * 6/10 = (35 * 6) / (42 * 10) = 7 / (7 * 2) = 1/2.