Answer: (-1, 1)
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Step-by-step explanation:
The rotation rule we use is

The x and y coordinates step places, then the second coordinate (after the swap) changes in sign from positive to negative, or vice versa.
For example, the point (5,7) rotates to (7, -5). As another example, (2,-1) becomes (-1, -2). As another example, (-9,4) becomes (4,9).
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In our case, the point (-1,-1) will rotate to (-1, 1)
Note: A 270 degree counterclockwise rotation about the origin is the same as a 90 degree clockwise rotation about the origin. Refer to the diagram below.