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2021 AMC 10B Problem 9

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2021 AMC 10B Problem 9AMC 10 Step by Step
Name:                             Date: September 13, 2026
Coordinate Geometry · difficulty 2 of 5 · about 3 min · position P1-10

The point P(a,b)P(a,b) in the xyxy -plane is first rotated counterclockwise by 90∘90^\circ around the point (1,5)(1,5) and then reflected about the line y=−xy = -x . The image of PP after these two transformations is at (−6,3)(-6,3) . What is b−a ?b - a ?

  1. A)

    11

  2. B)

    33

  3. C)

    55

  4. D)

    77

  5. E)

    99

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