To simplify the expression \( 5^9 \cdot 5^{-13} \) using the laws of exponents, we can apply the rule that states when multiplying expressions with the same base, you add their exponents:
\[ a^m \cdot a^n = a^{m+n} \]
In this case, we can apply this rule:
\[ 5^9 \cdot 5^{-13} = 5^{9 + (-13)} = 5^{9 - 13} = 5^{-4} \]
Next, to express \( 5^{-4} \) using only positive exponents, we can use the property that states \( a^{-n} = \frac{1}{a^n} \):
\[ 5^{-4} = \frac{1}{5^4} \]
Thus, the equivalent expression to \( 5^9 \cdot 5^{-13} \) with only positive exponents is:
\[ \frac{1}{5^4} \]