Advanced Math practice question

Answer: 20

(x + y)² − (x² + y²) = 2xy = 2(5)(2) = 20. (Directly: 49 − 29 = 20.)

Common wrong answers

If you answered 0

0 assumes (x + y)² = x² + y².

If you answered 10

10 is xy, counting the cross term once.

If you answered 49

49 is (x + y)² alone.

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