Find the infinite sum (if possible).

1. $6+3+\frac{3}{2}+$ ... 

   Hint (a):

   How is this sequence progressing? How will that help you to find the sum?

   Answer (a):

   $12$

2. $\displaystyle\sum_{k=1}^{∞}(\frac{1}{3})^k$ 

   Hint (b):

   What are the first term and multiplier of the sequence?