Final answer:
The rule for reflecting across the line y = x is to swap the x and y coordinates of each point.
Step-by-step explanation:
The rule that describes a reflection across the line y = x is that the x and y coordinates of each point are swapped. This means that if a point (x, y) is reflected across the line y = x, the reflected point will be (y, x).
For example, if the point (3, 4) is reflected across the line y = x, the reflected point will be (4, 3).
Similarly, for a given function g(x, y), when reflected across the line y = x, the function becomes g(y, x).
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