What transformation is represented by the rule (x, y)→(y, − x) ?

The answer is reflection around an X axis.

Step-by-step explanation:

In order to determine the answer, we have to know about reflection procedure.

A reflection procedure is when any figure, line or point is drawing again with different coordinates, but maintaining the geometry. It is the same effect that is produced by a mirror.

The reflection happens around an axis. The condition (x,y)→(y, − x) happens when we use the X-axis.

Finally, the transformation is represented by a reflection around an X axis.

answer: the answer is 127 degrees