Advanced Math practice question

Answer: 25

A perfect square (x + a)² = x² + 2ax + a². Here 2a = 10, so a = 5 and c = a² = 25.

Common wrong answers

If you answered 5

5 is a, not a².

If you answered 10

10 is the coefficient b, not c.

If you answered 100

100 is 10², squaring the whole coefficient instead of half of it.

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