Answer:
The nth term is given by: [tex]a_n = -9 + 3(n-1)[/tex]
The 30th term is 78.
Step-by-step explanation:
Arithmetic sequence:
The nth term of an arithmetic sequence is given by:
[tex]a_n = a_1 + (n-1)d[/tex]
In which [tex]a_1[/tex] is the first term and d is the common difference between terms.
-9, -6, - 3,0
This means that [tex]a_1 = -9, r = -6 - (-9) = -6 + 9 = 3[/tex]. So
[tex]a_n = -9 + 3(n-1)[/tex]
30th term:
[tex]a_30 = -9 + 3(30-1) = -9 + 87 = 78[/tex]
The 30th term is 78.