Advanced Math practice question

Answer: 6

(x + 3)² = x² + 6x + 9; subtracting x² + 9 leaves 6x.

Common wrong answers

If you answered 0

0 assumes (x + 3)² equals x² + 9.

If you answered 3

3 counts only one of the two 3x terms.

If you answered 9

9 is the constant term, which cancels.

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