[tex]\sf (6^{n+2}-6^n)\div(6^{n+1}+6^n) =(36\cdot 6^n-6^n ):(6\cdot 6^n +6^n )=\\\\ (35\cdot \backslash\!\!\!6^n)\div(7\cdot \backslash\!\!\! 6^n )=35:7=\boxed{5}[/tex]
