Given data:
The given sequence is 9, 20, 31, 42....
The first term is,
[tex]a=9[/tex]The common difference is,
[tex]\begin{gathered} d=20-9 \\ =11 \end{gathered}[/tex]The expression for nth term is,
[tex]a_n=a+(n-1)d[/tex]Substitute 9 for a, and 11 for d in the above expression.
[tex]\begin{gathered} a_n=9+(n-1)11 \\ =9+11n-11 \\ =11n-2 \end{gathered}[/tex]Thus, the expression for nth term is 11n-2.
