To factor the expression \( 9 - 36x \), we can first look for the greatest common factor (GCF) of the terms.
The GCF of \( 9 \) and \( 36 \) is \( 9 \).
Now, we can factor \( 9 \) out of the expression:
\[ 9 - 36x = 9(1 - 4x) \]
Thus, the completely factored form of the expression \( 9 - 36x \) is:
\[ 9(1 - 4x) \]