Elementary Geometry for College Students (7th Edition)

Given: The y axis is the perpendicular bisector of Line Segment AB. Find the coordinates of R if S is the point (-3, 7). As y-axis is the Perpendicular bisector of Line Segment AB, Line Segment AB has to be Parallel to the x-axis. One end of the line segment is given as (-3, 7) so the other end would simply be a "Reflection" of the given value. This is because y-axis is the perpendicular bisector of the given line segment. Therefore, the coordinates of point S would be (3, 7). Reflection over y-axis: $(x, y) => (-x, y)$