Advanced Math practice question

Answer: 28

(x + 2)³ = x³ + 6x² + 12x + 8 and (x − 2)³ = x³ − 6x² + 12x − 8. Subtracting, the x³ and 12x terms cancel: 12x² + 16. So a + b = 12 + 16 = 28.

Common wrong answers

If you answered 0

0 comes from assuming everything cancels; the x² and constant terms double rather than cancel.

If you answered 12

12 is a alone.

If you answered 16

16 is b alone.

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