Respuesta :

midpoint of (x1,y1) and (x2,y2) is

((x1+x2)/2,(y1+y2)/2)

just average the x and y values

(5,-8) and (10,18)
((5+10)/2,(-8+18)/2)
(15/2,10/2)
(7.5,5)

the midpoint is (7.5,5)