Find the first five terms of the sequence described. a1=3, an+1=an+5 8. Find the sum of the infinite series, if it exists. 100+20+4+… 9. Find the sum of the geometric series. ∑k=232[9(−1)k−1] 10. Find the indicated term of the arithmetic sequence. Find a23 in the sequence −18, −34, −50, −66, … 11. Find the first three terms of the arithmetic series described. n=16, an=15, Sn=−120 12. Find the first three terms of the arithmetic series described. n=15, an=45, Sn=45 13. Find the sum of the infinite series, if it exists. −270+135−67.5+… 14. Find S9 for the geometric sequence: an=2∙5n−2