Solve x squared negative 8 x is equal to 20 by completing the square. Which is the solution set of the equation?

To complete the square in x² − 8x = 20, take half of −8 and square it: (−4)² = 16. Add 16 to both sides to get (x − 4)² = 36, so x − 4 = ±6. Therefore x = 10 or x = −2, giving the solution set {−2, 10}, choice A.

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