Answer: [tex]\bold{a_1 = 6,\quad a_n=-3a_{n-1}}[/tex]
Step-by-step explanation:
[tex]\text{When given the value of the previous term, we can use the recursive formula:}\\ a_n = ra_{n-1}\ \text{where r is the common ratio, n is the term, and}\ a_{n-1}\ \text{is the previous term.}[/tex]
[tex]\text{In the given sequence, r} = \dfrac{-18}{6}=-3[/tex]
[tex]\rightarrow \ a_n=-3a_{n-1}[/tex]
