Answer:
[tex]a_{n}[/tex] = - [tex]\frac{1}{4}[/tex] [tex]a_{n-1}[/tex]
Step-by-step explanation:
The recursive formula lets us find a term in the sequence by multiplying the previous term by the common ratio r
Here r = [tex]\frac{20}{-80}[/tex] = [tex]\frac{-5}{20}[/tex] = - [tex]\frac{1}{4}[/tex]
Then recursive formula is
[tex]a_{n}[/tex] = - [tex]\frac{1}{4}[/tex] [tex]a_{n-1}[/tex]