How to Solve the following Sum? $\sum_{i=1}^{80} (3^i+3\times 2^i)$

I tried plugging in $i = 1$, and got $9$ as the output, following the same procedure, plugging in $i=2$ gave me $21$. I took note of $21/9$, but noticed the 3rd term divided by the second term $(51/21)$ did not give the same ratio, so somehow this is not a arithmetic or geometric series? Any help would be much appreciated.
$$\sum_{i=1}^{80}\left( 3^i + 3\times2^i\right)=\sum_{i=1}^{80}3^i + 3\sum_{i=1}^{80}2^i$$

So the series has been split into the sum of two geometric series which you can tackle with the standard tactic and combine to get your answer.
Hint:  Write out several terms of a sum on x^i.  Now multiply that by 1-x and see what happens when you cancel terms.  (1 + x + x^2 + x^3 +...+x^N)(1 - x).  Lots of terms will cancel, but there will be terms a 1 and a x^(N+1) that don't cancel.