It is: 13/17
43/34 is in its simplest form.
34/57 is in its simplest form.
34 over 42 in simplest form = 17/21
5/34 is already in its simplest form
34 over 59
34 / 30 = 17 / 15 in its simplest form.
34/68 = 1/2
34/100 = 17/50
34/51 = 2/3
18/34 = 9/17
34/32 = 17/16