Advanced Math practice question

Answer: 16

(x + k)² = x² + 2kx + k². Matching 2k = 8 gives k = 4, so c = k² = 16.

Common wrong answers

If you answered 4

4 is k, not c = k².

If you answered 8

8 is the coefficient b, not c.

If you answered 64

64 is 8², squaring the whole coefficient instead of half of it.

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