To rotate a point \((x, y)\) by 90 degrees counterclockwise about the origin, the new coordinates \((x', y')\) can be found using the following transformation rules:
\[ (x', y') = (-y, x) \]
Now, let's apply this to the point \(W (-4, 7)\).
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Identify the coordinates of W:
- \(x = -4\)
- \(y = 7\)
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Apply the rotation rules:
- For \(W'\), the new coordinates will be: \[ x' = -y = -7 \] \[ y' = x = -4 \]
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Combine the results:
- The coordinates of \(W'\) after the rotation are: \[ W' = (-7, -4) \]
Thus, the coordinates of \(W'\) after a 90-degree rotation about the origin are \(\boxed{(-7, -4)}\).