Not sure where to go with this:

$\displaystyle

\sum{3^n\over(1-2x)^n*n!}

$

I tried breaking it up into:

$\displaystyle \sum{1\over(1-2x)^n}$ + $\displaystyle \sum{3^n\over n!}$

Then

$\displaystyle \sum{3^n\over n!}$ would become $\displaystyle e^3-1$

And now I'm stuck.