What's the answer and what are the steps

The easiest thing to do first is to make them like fractions.  The first number where 5 and 8 meet, is 40.  So it becomes 12 25/40 and 7 16/40.  So we need to subtract 12 from 7 and that gives us 5.  Then we subtract 16 from 25 and get 9.  So our new number is 5 and 9/40.   Thats the answer.

I  dont  know much about vertexes but i know to solve this function you need to use foil method and then corresponmd the vertex with the actual coordinates, hope i !