Use the Formula for the General Term (The Nth Term) $$a _ { 1 } = - 9 , d = - 0.5$$

Multiple Choice

Use the formula for the general term (the nth term) of an arithmetic sequence to find the indicated term of the sequence with the given first term, a1, and common difference, d.
- $$a _ { 1 } = - 9 , d = - 0.5$$

A) $a _ { n } = - 9 n + 8.5 ; a _ { 20 } = - 171.5$
B) $a _ { n } = - 0.5 n - 9 ; a _ { 20 } = - 19$
C) $a _ { n } = - 0.5 n - 8.5 ; a _ { 20 } = - 18.5$
D) $a _ { n } = - 9 n - 0.5 ; a _ { 20 } = - 180.5$