Find an equation for the perpendicular bisector of the line segment whose endpoints are (-8,7) and (4,3)

Answer 1

slope of original line = (3-7)/(4+8) = -4/12 = -1/3
so the slope of our line = +3
so
y = 3 x + b
it goes through the point halfway between those two original ones
x = (-8+4)/2 = -2
y = (7+3)/2 = 5
so (-2 , 5)
use that to find b