To find the term a23 you have to replace 23 where it says 'n':
[tex]a_n=\frac{11}{8}+\frac{1}{2}n[/tex][tex]a_{23}=\frac{11}{8}+(\frac{1}{2}\times23)=\frac{11}{8}+\frac{23}{2}=\frac{11+92}{8}=\frac{103}{8}=12.875[/tex]
The answer is:
[tex]a_{23}=\frac{103}{8}=12.875[/tex]
