Could someone help with this precalculus problem?

8.28 Show that the equation of the perpendicular bisector of the line segment with endpoints (x1,y1) and (x2,y2) can be written (x4 - x3 / y2 - y1) + (y4 - y3 / x2 - x1) = 0, where (x3,y3) are the coordinates of the midpoint of the segment.