Solve x squared plus 6 x is equal to 7 by completing the square. Which is the solution set of the equation?

To complete the square, add 9 to both sides: x² + 6x + 9 = 7 + 9, so (x + 3)² = 16. Taking square roots gives x + 3 = 4 or x + 3 = −4, so x = 1 or x = −7. The solution set is {−7, 1}, choice B.

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