A line segment has endpoints at (–1, 4) and (4, 1). Which reflection will produce an image with endpoints at (–4, 1) and (–1, –4)?

 (–1, 4) to (–4, 1) and (4, 1) to (–1, –4)
so
The rule is (x,y) --> (-y,-x)

The reflection over y = - x

hope it helps