If you mean to say to find the 11th term, then know that this is an arithmetic sequence (where you have a common difference).
The common difference in this case is -2.
The formula for finding any term in an arithmetic sequence (specifically the explicit formula) is: [tex]a_n = a_1 + (n-1)d[/tex] where a_n is the term, a_1 is the first term, n is the term number (position) and d is the common difference.
Let's substitute the corresponding values to the formula.
[tex]a_{11} = 3 + (11-1)-2
a_{11} = 3 + (10)-2
a_{11} = 3 - 20
a_{11} = -17
[/tex]
The 11th term is -17.
