Question 389531
1. First find the slope of the line segment then find the midpoint of the line segment
Using the coordinates of the two end points, (-1,1) and (7,5),
slope =∆y/∆x =(1-5)/(-1-7)=-4/-8 =1/2
midpoint =  (x1+x2)/2,(y1+y2)/2=(-1+7)/2,(1+5)/2=(3,3)

slope of perpendicular bisector = negative reciprocal or line segment = -2
using this slope, the coordinates of the midpoint (3,3), and the point slope formula,y=mx+b
3=-2*3+b
b=3+6=9
equation then becomes, y=-2x +9

ans: the equation of the perpendicular bisector of a line segment whose endpoints are (-1,1) and (7,5)
        is y=-2x+9