The explicit formula of the arithmetic sequence:
[tex]a_n=a_1+(n-1)d[/tex]
d - common difference
We have the recursive formula of an arithmetic sequence:
[tex]\left\{\begin{array}{ccc}a_1=4\\a_n=a_{n-1}-3\end{array}\right[/tex]
Therefore we have:
[tex]a_1=4,\ d=-3[/tex]
Substitute:
[tex]a_n=4+(n-1)(-3)=4-3n+3=7-3n[/tex]
Answer: aₙ = 7 - 3n
