Answer:
(-18, 2)
Explanation:
To rotate a point by 90°:
R₉₀ (x, y) = (-y, x)
R₉₀ (1, 9) = (-9, 1)
To dilate by 2:
D₂ (x, y) = (2x, 2y)
D₂ (-9, 1) = (-18, 2)
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