What is the coefficient of the x to the 4th power -term in the binomial expansion of open paren x plus 3 close paren to the 12th power ?

By the binomial theorem, the term containing x⁴ in (x + 3)¹² is formed by choosing x from 4 of the 12 factors and 3 from the other 8. Its coefficient is C(12, 4) · 3⁸, which equals C(12, 8) · 3⁸ because C(12, 4) = C(12, 8). Therefore, the coefficient is 12C8 · 3⁸, choice A.

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