To solve the equation \( 5^x = 625 \), we can express 625 as a power of 5.
We know that: \[ 625 = 5^4 \]
So, we can rewrite the equation as: \[ 5^x = 5^4 \]
Since the bases are the same, we can set the exponents equal to each other: \[ x = 4 \]
Therefore, the solution is \( x = 4 \).
So, the correct response is: x is equal to 4.