2)6/14;10/22;12/14;14/16;18/28
Только

1) 6/14 = (2 * 3)/(2 * 7) = 3/7.

2) 10/22 = (2 * 5)/(2 * 11) = 5/11.

3) 12/14 = (2 * 6)/(2 * 7) = 6/7.

4) 14/16 = (2 * 7)/(2 * 8) = 7/8.

5) 18/28 = (2 * 9)/(2 * 14) = 9/14.д

20/26=(10*2)/(13*2)=10/13

Не за что)