If the perimeter is 14. Add 2,4, and 5 which is 11. Then find out how many meters does it take to get from 11 to 14. In this case the answer is 3
3x+5=0
3x=0-5
3x=-5
Divide both sides by 3
-1.6666.......
Hope it helps.
As for mod 9, I don't understand.
Your answer will be 406 hope this helps