easy, remember rules of exponents
the only one you need to know for this question is this one: [tex]\frac{x^m}{x^n}=x^{m-n}[/tex]
also [tex]x^{-m}=\frac{1}{x^m}[/tex]
so in this case
[tex]\frac{5^5}{5^8}=5^{5-8}=5^{-3}=\frac{1}{5^3}[/tex]
answer is 1st option
