Answer:
[tex]a_{n}[/tex] = 4n + 11
Step-by-step explanation:
There is a common difference between consecutive terms, that is
19 - 15 = 23 - 19 = 4
This indicates the sequence is arithmetic with explicit rule
[tex]a_{n}[/tex] = a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = 15 and d = 4 , then
[tex]a_{n}[/tex] = 15 + 4(n - 1) = 15 + 4n - 4 = 4n + 11