Advanced Math practice question

Answer: -9

x² = 81 has solutions 9 and −9; the negative one is −9.

Common wrong answers

If you answered 9

9 is the positive square root.

If you answered -81

−81 is the negative of the product, not a square root.

If you answered -40.5

−40.5 halves 81 instead of taking a square root.

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