To rewrite \( 15^{-38} \) with positive exponents, you can use the property of negative exponents, which states that \( a^{-n} = \frac{1}{a^n} \).
Applying this property, we have:
\[ 15^{-38} = \frac{1}{15^{38}} \]
So, the rewritten expression with positive exponents only is:
\[ \frac{1}{15^{38}} \]