Ответ:

1.

а) 7/10 * 4/9 = 7/5 * 2/9 = 14/45

б) 6/11 * 1/6 = 1/11

в) 5/7 * 14/17 = 5 * 2/17 = 10/17

г) (4/9)^2 = 4^2/9^2 = 16/81

д) 4/11:5/12 = 4/11 * 5/12 = 48/55

е) 30/7:5/14 = 30/7 * 14/5 = 6 * 2 = 12

ж) 6/19:3 = 6/19 * 1/3 = 2/19

з) 8:2/5 = 8 * 5/2 = 4 * 5 = 20

2.

а) 4 * (12/15:6/5) = 4 * (12/15*5/6) = 4 * 2/3 = 8/3

б) 15/23:5/6 * 23/24 = 15 * 6/5 * 1/24 = 3 * 1/4 = 3/4

в) 2/9 * 9/10 * 10/13 * 13/12 = 2 * 1/10 * 10/13 * 13/12 = 2 * 1/13 * 13/12 = 2 * 1/12 = 1/6