Question #1:
Just divide the side lengths to find the scale factor.
8 / 2 = 4.
Therefore the scale factor from MNO to M'N'O' is 4.
Question #2:
Rotation rule for 180 degree clockwise turn: (-x, -y)
Therefore your new points will be:
(5, 2), (5, 4), and (4, 4)
