Use the Formula for the General Term of an Arithmetic $a 18$

Multiple Choice

Use the Formula for the General Term of an Arithmetic Sequence
Choose the one alternative that best completes the statement or answers the question.
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.
-Find $a 18$ when $a _ { 1 } = 10 , d = - 1$ .

A) $- 7$
B) $- 8$
C) 27
D) 28 8