Each of the following sums is the beginning of an arithmetic series. Find the $n$^th term of each series, for the specified value of $n$.

1. $(-2) + (-5) + (-8) +$ ..., $n = 12$ 

   Hint (a):

   How is this sequence progressing?
   How can you use that to determine what the $12$th term will be?

   Answer (a):

   $-35$

2. $9 + 15 + 21 +$ ..., $n = 20$ 

   Hint (b):

   Use the same method as part (a).