midpoint means that the line segments beside the midpoint are same legnth
therefor QP=PR in legnth
therefor
2x-6=x+7
solve
remember thath you can do antyhingn to an equaiton as long as you do it to both sides
2x-6=x+7
minus x from both sides
2x-x-6=x-x+7
x-6=0+7
add 6 to both sides
x+6-6=7+6
x=13
qr=pr
pr=x+7
x+7=13+7=20
answer is 20 units
