For items \( 6 \mathbf{- 1 0} \), find specified geometric series of the following geometric sequences:
6.) \( 3,12,48, \ldots \quad S_{7} \)
7.) \( 2,6,18, \ldots \quad S_{6} \)
8.) \( 125,25,5, \ldots \quad S_{8} \)
9.) First term \( a_{1}=2 \) and common ratio \( r=-4 \); find \( S_{8} \)
10.) First term \( a_{1}=\frac{1}{2} \) and common ratio \( r=-2 \); find \( S_{6} \)
For items 11 - 15, find the geometric series of each infinite geometric sequence.
11.) \( 12,6,3, \ldots \)
12.) \( 125,25,5, \ldots \)
13.) \( 1, \frac{1}{5}, \frac{1}{25}, \ldots \)
14.) \( 15,5, \frac{5}{3}, \ldots \)
15.) \( 1, \frac{2}{3}, \frac{4}{9}, \ldots \)
