Question 203905
The line {{{x=2}}} is a vertical line thru the point (2,0).
You are asked to find point B such that the line x=2, is both perpendicular to and bisecting the line segment AB

Since {{{x=2}}} is vertical (an undefined slope), then the segment AB must be horiztonal. In order to horizontal, the y coordinate from B must be the same as the y coordinate in point A.
so B = {{{someXvalue, 1}}}
The x coordinate of A is -4, so that coordinate is 2 - (-4) = 6 units from the nearest point on the line {{{x=2}}}
In order to be  bisector, that means the closest point to B is also a distance of 6.
so B = {{{2+6,1}}} = {{{8,1}}}

Now plot them and see if the logic works :)