Thread: it lost me

What is the coefficients of x^8 y^9 in the expansion of (3x + 2y)^17?

Originally Posted by lkrb

What is the coefficients of x^8 y^9 in the expansion of (3x + 2y)^17?

Just use the binomial theorem.

Originally Posted by lkrb

What is the coefficients of x^8 y^9 in the expansion of (3x + 2y)^17?

Originally Posted by janvdl

Just use the binomial theorem.

correct. to be more specific. the formula for binomial expansion is:



though i much prefer it in the order (it's exactly the same thing) of


Here you have and , and you want the term given by (using the second formula)

Just like guys here mentioned... you use binomial theorem. So your final answer would be [17! / (8! * 9!)] * (3^8) (2^9).