# Write a formula for the general term (the nth term) of the geometric sequence 4, 12, 36, 108, 324, . . .

Write a formula for the general term (the nth term) of the geometric sequence 4, 12, 36, 108, 324, . . .
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bibliothecaqz
The general term of any geometric sequence $\left({x}_{n}\right)$ is given by
${x}_{n}=a{r}^{n-1}$, where a is the first term and r is the common ratio defined as $r=\frac{{x}_{n+1}}{{x}_{n}}$.
So in this case a=4 and $r=\frac{21}{4}=3$
$\therefore {x}_{n}=4\cdot {3}^{n-1}$