Find an equation for the perpendicular bisector of the line segment whose endpoints are (-1,7) and (9,−3).
for the line joining the points,
the midpoint is (4,2)
the slope is -1
so you want a slope of 1, making the equation
y-7 = -1(x+1)
slope of the line formed by the 2 points
= (-3-7)/(9+1)
= -10/10 = -1
so the slope of the perpendicular is +1
midpoint of the 2 points
= ((-1+9)/2 , (7-3)/2 )
= (4, 2)
equation: y - 2 = 1(x - 4)
or
y = x - 2