## College Algebra (6th Edition)

The nth term of a geometric sequence can be obtained by the following formula: $a_n=a_1+(n−1)d,$ where $a_1$ is the first term and $d$ is the common difference. As we can see here:$a_1=3,d=-5$. Thus $a_n=3+(n-1)-5=3-5n+5=8-5n$ Hence here: $a_{20}8-5\cdot20=8-100=-92$