Answer: J' (8, -9); K' (8, -2); L' (3, -2); M' (3, -9)
Explanation:
A rotation of 90 degrees counterclockwise is (x, y) -> (-y, x), so
J (-9, -8) -> J' (8, -9)
First, you take negative 8 (y) of J and make it positive 8 for the x of J'. Then, take -9 (y) of J and switch it to x of J'.
You repeat this process for the rest of the points. X switches to Y with the opposite sign and Y switches to X but stays the same.
K (-2, -8) -> K' (8, -2)
L (-2, -3) -> (3, -2)
M (-9, -3) -> (3, -9)