r(x) = –x² + 3x s(x) = 2x + 1(s – r)(x) =

To find (s − r)(x), subtract r(x) from s(x): (2x + 1) − (−x² + 3x). Distributing the subtraction gives x² − 3x + 2x + 1 = x² − x + 1, so choice C has the correct setup.

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