Solve x squared plus 12 x is equal to negative 11 by completing the square. Which is the solution set of the equation?

Start with x² + 12x = −11. Add (12 ÷ 2)² = 36 to both sides to complete the square: (x + 6)² = 25. Taking square roots gives x + 6 = 5 or x + 6 = −5, so x = −1 or x = −11. The solution set {−11, −1} is choice D.

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