Answer with explanation:
The Meaning of reflection of a point through any of the axis states that,the perpendicular distance of a point from either of the axes chosen as line of reflection from Image and Preimage is constant.
⇒Preimage = (2, -1)
Marking the point in x y Plane and then Plotting it's reflection in x y plane
⇒ Image = (2, 1)
In the first Quadrant.