Recall that a 90 degree rotation counterclockwise around the origin implies the following transformation of coordinates:
(x, y) --> (-y, x)
Therefore, the rotation in 90 degrees counterclockwise for ( -3, 7) becomes:
(-3, 7) --> (-7, -3)
The going backward with the rotation of 90 degrees around the origing will get us back to the exact orginal point.
Please allow me a little time to make the drawing with the transformed point.
You can see the red point image of point A after the 90 degree rotation. Notice as well the green angle marked with vertex at the origin showing the 90 degree counterclockwise rotation
A rotation 90 degrees clockwise will produce the following result:
(-3, 7) --> (7, 3)
which is shown in the following image
So we see that the transformation is of the form:
(x, y) --> (y, -x)
