Answer:
[tex]a_{n}[/tex] = 6n - 3
Step-by-step explanation:
There is a common difference d between consecutive terms, that is
d = 9 - 3 = 15 - 9 = 21 - 15 = 6
This indicates the sequence is arithmetic with n th term
[tex]a_{n}[/tex] = a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = 3 and d = 6, then
[tex]a_{n}[/tex] = 3 + 6(n - 1) = 3 + 6n - 6 = 6n - 3
