To simplify the expression \( (5^6)^{-5} \), we can use the power of a power property of exponents, which states that \( (a^m)^n = a^{m \cdot n} \).
Applying this to our expression:
\[ (5^6)^{-5} = 5^{6 \cdot (-5)} \]
Now, we calculate \( 6 \cdot (-5) \):
\[ 6 \cdot (-5) = -30 \]
So we have:
\[ (5^6)^{-5} = 5^{-30} \]
Thus, the expression \( (5^6)^{-5} \) is equivalent to \( 5^{-30} \).