#### Answer

$a_{20}=-83$

#### Work Step by Step

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:
$a_{20}=12+(-5)\times(20-1)=12-95=-83$
$a_{20}=-83$