To find the coefficient of \( x^8y^9 \) in the expansion of \( (3x + 2y)^{17} \), we can use the Binomial Theorem, which states that:
\[
(a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k
\]
In our case, \( a = 3x \), \( b = 2y \), and \( n = 17 \).
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