Please help...

1.) find the series' radius and interval of convergence. for what values of x does the series converge absolutely and conditionally?

∞

Σ [(3^n)(x^n)] / (n!)

n=0

2.) find the sum of the series by expressing 1/ (1-x) as a geometric series

∞

Σ (n^2)/(2^n)

n=0