It is already simplified as 13/15
No, 13/15 is a simplified as far down as possible.
15/65 = 3/13
15/43 is simplified.
39/45 can be simplified to 13/15.
13/9 cannot be simplified.
15/48 is simplified to 5 over 16
-13/72 cannot be simplified.
Yes, it is simplified.
It is already simplified.
The simplified fraction of 15 over 63 is 5/21
It can't be simplified.