We have the following:
Since it is a square, the sides are equal, and the perimeter is the sum of all the sides, therefore it would be
[tex]\begin{gathered} p=4\cdot l \\ l=2n-3 \\ \text{replacing} \\ p=4\cdot(2n-3) \\ p=8n-12 \end{gathered}[/tex]The answer is 8n - 12