Answer :
According to the problem, the recursive rule is
[tex]\begin{gathered} f(1)=15 \\ f(n)=f(n-1)-6 \end{gathered}[/tex]This means the first term of the sequence is 15.
So, for n = 2, we have
[tex]f(2)=f(2-1)-6=f(1)-6[/tex]But, we know that f(1) = 15, so
[tex]f(2)=15-6=9[/tex]The second term is 9.
For n = 3.
[tex]f(3)=f(3-1)-6=f(2)-6[/tex]But, we know that f(2)=9, so
[tex]f(3)=9-6=3[/tex]