Answer
In this explicit form we see that $r$ =|$0.73|\lt1 $ which means that this geometric series will converge.
Now, use the formula from definition 4 in page 750 , knowing that $a$ refers to the first term which is $12$ and using the explicit $r$ and we get
$S= \frac{a}{1-r}$ = $\frac{12}{1-0.73} = \frac{12}{0.27} = \frac{400}{9}$
Result: the series converges and its sum is $\frac{400}{9}$ .
Work Step by Step
This attached image details the steps of finding the answer
