ANSWER
[tex]a_{55}=161[/tex]
EXPLANATION
The general term for the sequence is
[tex]a_n=-1+3(n-1)[/tex]
To find the 55th term, we have to substitute
[tex]n = 55[/tex]
in to the general term and simplify.
This implies that,
[tex]a_{55}=-1+3(55-1)[/tex]
[tex]a_{55}=-1+3(54)[/tex]
[tex]a_{55}=-1+162[/tex]
[tex]a_{55}=161[/tex]
Therefore the 55th term is 161.