To solve the equation \( \frac{5^x}{5^5} = 5^{12} \), we can use properties of exponents.
Recall the property of exponents that states:
\[ \frac{a^m}{a^n} = a^{m-n} \]
This allows us to simplify the left side of the equation:
\[ \frac{5^x}{5^5} = 5^{x-5} \]
Now, we can rewrite the equation as:
\[ 5^{x-5} = 5^{12} \]
Since the bases are the same, we can set the exponents equal to each other:
\[ x - 5 = 12 \]
To find \( x \), we can solve for it:
\[ x = 12 + 5 \] \[ x = 17 \]
Thus, the value of \( x \) that makes the equation true is
\[ \boxed{17} \]