Expert: Abe Mantell - 7/8/2008

Question
I have a study question and I can't figure out how to approach solving it. I cannot get the correct answer no matter which method I try.  I can't figure out what I am doing wrong.  

The question:
Point A (-4,1)is in the standard x-y coordinate plane. What must be the coordinates of point B so that the line x=2 is the perpendicular bisector of AB. [The AB has a line over it, which I assume means it's a formula and the AB is the denominator.

The answer is (8,1)

I've tried using the formula y = mx + b, then using an x chart, but to no avail.  Could you tell me how to approach such a question so I can properly solve one like this?  

thank you very much!
Becky in KY

Answer
Hello Becky (in KY)!

If we want the vertical line x=2 to be perpendicular to the segment,
then the segment must be horizontal.  Thus, the y-coordinate must be
the same as the given point...so y=1.  Now, if we want x=2 to bisect
the segment, then we need the point to be the same distance away from
x=2 as is the point (-4,1).  Since the distance from x=2 to (-4,1) is
2-(-4)=6, we need the x-coordinate to be 2+6 (6 units to the right of
x=2).  So, the point must be (8,1).

OK?

Abe (in NY) ;->