Question

Find the fifth term of (2x + y)^10

Answer 1

\((A+B)^n=nC0 A^0B^n+nC1 A^1B^{n-1}+...nCnA^nB^0\)
So the 5th term is
\(nC4A^4B^{n-4}\)
where nCr="n choose r"=n!/(r!(n-r)!)
For the given question, A=2x, B=y.