midpoint (x,y) = (x1 + x2)/2, (y1 + y2)/2
=-2,1 = (x1 + -7)/2, (y1 + 2)/2
-2 = (x1 - 7)/2 1 = (y1+2)/2
-4 = x1 - 7 2 = y1 + 2
3 = x1 0 = y1
coordinate of J is (3,0)
coordinate of L is (-7,2)
distance between (x1,y1) and (x2,y2)
= sqrt ( (y2-y1)^2 + (x2-x1)^2)
distance = sqrt( (2-0)^2 + (-7-3)^2) = sqrt(4+100) = sqrt(104) = 10.2