Question

A point has the coordinates (m, 0) and m ≠ 0.

Which reflection of the point will produce an image located at (0, –m)?

a reflection of the point across the x-axis
a reflection of the point across the y-axis
a reflection of the point across the line y = x
a reflection of the point across the line y = –x

Answer 1

Reflection across the line y = −x.

Reason: reflection across y = −x sends (x,y) to (−y, −x). Applying this to (m,0) gives (0, −m).