[tex](x,y)\to(y,-x)[/tex]
1) In this question, we need to consider that when we rotate it 270º CCW that figure is going to be rigid moved 270º to the left.
2) So, we can write out the vertices:
Pre-image Rule Image
(5,4) (x,y)->(y,-x) (4,-5)
(3,4) (4,-3)
(3,1) (1,-3)
(4,1) (1,-4)
3) Therefore, the answer is:
[tex](x,y)\to(y,-x)[/tex]
Note that the image goes to Quadrant III
