SOLUTION: Find the fourth term of the binomial expansion... (3x+y)^6

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Question 302500: Find the fourth term of the binomial expansion...
(3x+y)^6
Answer by Nate(3500) About Me  (Show Source):
You can put this solution on YOUR website!
(A + B)^6 = ... + C(6,3)*A^3*B^3 + ...
B^3 determines the term number; here being the fourth because the first term began with B^0.
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(3x+y)^6 = C(6,3)*A^3*B^3 = 20(3x)^3(y)^3 = 540x^3y^3