Final answer:
A reflection across the line y = x flips points or figures across the line y = x by swapping the x-coordinate with the y-coordinate.
Step-by-step explanation:
A reflection across the line y = x is a transformation that flips a point or a figure across the line y = x. In this reflection, every point (x, y) is transformed to the point (y, x). The x-coordinate and y-coordinate of the original point are swapped to find the new coordinates after the reflection.
For example, if we have a point A with coordinates (3, 2), the reflection of point A across the line y = x will have coordinates (2, 3).
Another way to think of this reflection is that it is like folding the coordinate plane along the line y = x, with each point being reflected to its corresponding point on the other side of the line.
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