Answer
An equation for the $n^{th}$ term is
$a_n=8n$
and
$a_{25}=200$
Work Step by Step
The given arithmetic sequence is
$8,16,24,32,...$
The first term $a_1=8,$
and the common difference is $d=16-8=8$
The $n^{th}$ term formula is
$\Rightarrow a_n=a_1+(n-1)d$
Substitute $8$ for $a_1$ and $8$ for $d$.
$\Rightarrow a_n=8+(n-1)8$
Simplify.
$\Rightarrow a_n=8+8n-8$
$\Rightarrow a_n=8n$
Substitute $25$ for $n$.
$\Rightarrow a_{25}=8(25)$
Simplify.
$\Rightarrow a_{25}=200$.
