Question

find an explicit rule for the nth term of the sequence. -3, -15, -75, -375

Answer 1

$\begin{gathered} -3=-3\times1 \\ -15=-3\times5 \\ -75=-3\times25=-3\times5^2 \\ -375=-3\times125=-3\times5^3 \\ \\ \text{ the nth term of the sequence is then} \\ a_n=-3\times(5)^n \end{gathered}$