In order to calculate a rotation of 270° clockwise, we need to switch the values of the x and y coordinates of each point, and verify the new signal according the new quadrant the point will be:
P(2, 3) is in the 1st quadrant, after the rotation it will be in the 2nd one, so negative x and positive y, therefore we have P'(-3, 2)
I(7, -7) is in the 4th quadrant, after the rotation it will be in the 1st quadrant, so positive x and y, therefore we have I'(7, 7)
N(2, -7) is in the 4th quadrant, after the rotation it will be in the 1st quadrant, so positive x and y, therefore we have N'(7, 2)
Drawing the new image, we have: