You have to first write it as two terms, then you can apply the following:

Btw, by (n)(k) i meant nCk....I miss LaTeX :-(Code:n Sigma (n) x^(n-k)y^k k=0 (k)

EDIT: I was kind of vague. n represents the number of terms (like (x+y)^4, n = 4), so if you wanted the third term, you should do this:

EDIT2: Example: if i wanted to find the fifth term in the expansion of (x+y)^10, then:Code:(n) x^(n-2)y^2 (2)

- Identify n = 10

- I need fifth term, so k = 5 - 1 = 4.

- Evaluate :-)