Hello,

I was hoping to get a little help here. I have an assignment due in a couple of weeks, and one question is:

"Use the Binomial Theorem to determine the coefficient of x^15 in the expansion of (1/3x - 9)^20. Express your answer as a fraction in the lowest terms."

I am hoping that someone can point me in the general direction of been able to answer this one. I have read over the material, but just can't seem to get it.

Any help would be great.

Thanks.

Sean