Advanced Math practice question

Answer: 29

(2x + 5)(2x − 5) = 4x² − 25, so a + b = 29.

Common wrong answers

If you answered 7

7 uses a = 2 and b = 5, forgetting to square.

If you answered 21

21 subtracts 4 from 25.

If you answered -21

−21 subtracts the wrong way and mis-signs.

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