find reflection of (3,-2) across the line x=1
see the attached figure to better understand the problem
we have that
the distance of point P to the line of reflection (x=1) must be equal to the distance of the point (3,-2) to the line of reflection (x=1)
the distance d is equal to (3-1)=2 units
therefore
the coordinates of point P are
(1-2,-2)
P(-1,-2)
answer is
reflection is (-1,2)