Question 17 • Common Core Algebra I 2014 - MA3109 B-CR
A perfect square trinomial has the form x² + 2ax + a². Since the coefficient of x is 6, 2a = 6, so a = 3 and c = a² = 9. Thus, x² + 6x + 9 = (x + 3)², so the correct choice is 9.
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