The image shows a rotation problem asking to determine the coordinates of point $A'$ after a 90-degree rotation of point $A(2, 1)$.

To rotate a point 90 degrees counterclockwise around the origin, the transformation rule is: $(x, y) \to (-y, x)$

Applying this rule to $A(2, 1)$: $A(2, 1) \to A'(-1, 2)$

So, the coordinates of $A'$ after a 90-degree rotation are $A'(-1, 2)$.

Thus, the correct answer is: A'(-1, -2).

Would you like further explanation or details?

Related Questions:

1. How would the coordinates of $A(2, 1)$ change for a 180-degree rotation?
2. What is the transformation rule for a 270-degree counterclockwise rotation?
3. How would you perform a reflection over the x-axis for the point $A(2, 1)$?
4. What is the formula for rotating a point clockwise by 90 degrees?
5. How does a dilation from the origin affect the coordinates of a point?

Tip:

Remember that rotations are counterclockwise by default unless otherwise specified!