Answer:
A. [tex]\bold{a_n=-3\cdot\left(\frac18\right)^{n-1}}[/tex]
Step-by-step explanation:
[tex]\begin{cases}a_1=-3\\a_n=a_{n-1}\cdot\dfrac18\end{cases}\\\\\\a_2=a_{2-1}\cdot\frac18=a_1\cdot\frac18\\\\r=\dfrac{a_2}{a_1}=\dfrac{a_1\cdot\frac18}{a_1}=\dfrac18\\\\\\a_n=a_1\cdot r^{n-1}\\\\a_n=-3\cdot\left(\frac18\right)^{n-1}[/tex]
