To rewrite the expression \( 6^3 \cdot 6^5 \) using a single exponent, you can use the property of exponents that states \( a^m \cdot a^n = a^{m+n} \).
Applying this property here:
\[ 6^3 \cdot 6^5 = 6^{3+5} = 6^8 \]
So, the expression \( 6^3 \cdot 6^5 \) simplifies to \( 6^8 \).