How do I find the equation of a perpendicular bisector of a line segment with the endpoints (-2, -4)(2,4) and (6, 4)(6,4)?

1 Answer
Jul 16, 2016

x+y-2 = 0x+y2=0

Explanation:

Let (x,y)(x,y) be any point on the perpendicular bisector. From elementary geometry, we can easily see that this point must be equidistant from the two points (-2,-4) and (6,4)(2,4)and(6,4). Using the Euclidean distance formula gives us the equation

(x+2)^2 + (y+4)^2 = (x-6)^2 + (y-4)^2 (x+2)2+(y+4)2=(x6)2+(y4)2

This can be rewritten as

(x+2)^2 - (x-6)^2 = (y-4)^2-(y+4)^2(x+2)2(x6)2=(y4)2(y+4)2

Using a^2 -b^2 = (a+b)(a-b)a2b2=(a+b)(ab), this simplifies to

8(2x-4) = -8*2y8(2x4)=82y which simplifies to

x+y-2 = 0x+y2=0