3. Find the sum of the first n terms of each geometric series.
1. n= 6; -2-6-18-54 - ...
2. n=7; 1+3 + 9 + 27 + ...
3. n= 10; 5+10 + 20 + 40 + ..
4. n= 7; 1-5+25 - 125+ ...
_ 5. n= 10; 1 / 1
3 9 27
+ + - + +
2 2 2​