Why clueless? Do you not know what means? It is the "binomial coefficient" .
If you do know that, then this can be done by simple arithmetic:
Tedious, but just arithmetic. (I will admit that " " hides some pretty big numbers!)
But if you are clever, you will remember that "binomial coefficients" are so named because so that, if you take x= 1, .
What about that "p" multiplying the binomial coefficient? Think about the derivative of with respect to x.
It is posted in Pre-University algebra forum..
That has to be in most elementary forum on the entire board.
Therefore, I try to answer in that sprite.
If Petrus expects a high level answer then questions should be posted in an more appropriate forum.
I do not think the answer is appropriate for this forum.
Even if it is a well-known fact.