Answer: (2,0), (2,1), and (6,1)
Step-by-step explanation: I just used the desmos graphing calculator to find the answer to your problem. I don't know any formulas to solve it so I just rotated the points by hand. I also made sure they were still equidistant from the point (2,-1) because if their distances from other points changed during the rotation, then the triangle would not be equal to the first triangle and the image would've been distorted.
I hope this helps! Have a nice day.