Given the arithmetic sequence:
[tex]\begin{gathered} f(1)=5 \\ f(n)-f(n-1)=12 \end{gathered}[/tex]
The common difference of an arithmetic sequence is the constant difference between two consecutive elements. In this case, f(n) and f(n - 1) are two consecutive elements, and we already know the difference between them (12).
Then:
[tex]\text{Common difference }=12[/tex]
