To find the coordinates of point W' after a 90-degree counterclockwise rotation about the origin, we can use the rotation mapping rule for a 90-degree counterclockwise rotation, which is given by the transformation:
\[ (x, y) \rightarrow (-y, x) \]
For the point W(-3, 7):
- Identify the coordinates: \( x = -3 \) and \( y = 7 \).
- Apply the transformation: \[ W' = (-y, x) = (-7, -3) \]
Therefore, the coordinates of W' after a 90-degree counterclockwise rotation about the origin are:
\[ W'(-7, -3) \]