Question

Triangle XYZ is reflected across the line y = x, and X’ = (2, –15). What are the coordinates of X?
(–15, 2)
(–2, 15)
(2, 15)
(–15, –2 )

Answer 1

Reflection across the line y = x swaps coordinates: (x, y) ↔ (y, x).
Since X' = (2, −15), the original X = (−15, 2).