Answer
$a_n=a_1 \cdot r^{n-1}$;
$\text{first term}$;
$\text{common ratio}$
Work Step by Step
Recall:
In a geometric sequence, the $n^{\text{th}}$ term $a_n$ of is given by the formula:
$$a_n=a_1\cdot r^{n-1}$$
where
$a_1$=first term
$r$=common ratio
Thus, the missing expressions (in order) in the given statements are:
$a_n=a_1 \cdot r^{n-1}$;
first term;
common ratio
