Answer:
see attached
Explanation:
Rotation 270° counterclockwise is equivalent to rotation 90° clockwise. The transformation of coordinates is ...
(x, y) ⇒ (y, -x) . . . . . . . rotation 270° CCW
This means the points are moved to ...
A(-2, 1) ⇒ A'(1, 2)
B( 1, 2) ⇒ B'(2, -1)
C(-2, 4) ⇒ C'(4, 2)
The rotated triangle is shown in the attachment. You may notice that A' and B are the same point.