x = 5
1) Given that E is the Cicumcenter we can write the following about it
2) The distance from circumcenter to all of their vertices from that triangle are the same, so we can write:
NE =EP Line segments that connect the vertices N, and P
13x -28 = 6x +7
13x -6x = 28 +7
7x = 35
x= 5
3) Hence, x = 5