## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$a_{20}=-83$
The n th term of an arithmetic sequence can be calculated as: $a_n=a_1+d\times(n-1)$ Here: $n=20$, $d=-5$ and we have to find $a_{20}$. By substituting we get: $a_{20}=12+(-5)\times(20-1)=12-95=-83$ $a_{20}=-83$