To solve the equation \( 9x = 3x - 36 \), follow these steps:
- First, subtract \( 3x \) from both sides of the equation to isolate the variable on one side:
\[ 9x - 3x = -36 \]
- This simplifies to:
\[ 6x = -36 \]
- Next, divide both sides by 6 to solve for \( x \):
\[ x = \frac{-36}{6} = -6 \]
Thus, the solution is:
\[ \boxed{-6} \]
So the correct response is \( x = -6 \) (or \( x \text{ equals negative } 6 \)).