∆ABC is translated 2 units down and 1 unit to the left. Then it is rotated 90° clockwise about the origin to form ∆A′B′C′.
The coordinates of vertex A′ of ∆A′B′C′ are___
The coordinates of vertex B′ of ∆A′B′C′ are ___
The coordinates of vertex C′ of ∆A′B′C′ are ___
