Answer:
[tex]a_{n}[/tex] = - 1 [tex](-3)^{n-1}[/tex]
Step-by-step explanation:
The n th term ( explicit formula ) for a geometric sequence is
[tex]a_{n}[/tex] = a[tex](r)^{n-1}[/tex]
where a is the first term and r the common ratio
Here a = - 1 and r = - 9 ÷ 3 = 3 ÷ - 1 = - 3, thus
[tex]a_{n}[/tex] = - 1 [tex](-3)^{n-1}[/tex] with a₁ = - 1