Given the following sequence:
[tex]\mleft\lbrace17,14,11,8,\ldots\mright\rbrace[/tex]
notice that the common difference between each term is -3, therefore, we can use the explicit formula for a sequence:
[tex]\begin{gathered} a_n=a_1+(n-1)\cdot d \\ d=-3 \\ a_1=17 \\ \Rightarrow a_n=17+(n-1)(-3) \\ \Rightarrow a_n=17-3n+3=20-3n \\ a_n=20-3n \end{gathered}[/tex]
we have that the explicit formula is a_n=20-3n, while the recursive formula is:
[tex]\begin{gathered} a_n=a_{n-1}+d \\ d=-3 \\ \Rightarrow a_n=a_{n-1}-3 \end{gathered}[/tex]
