Let's solve the equation step by step.
Given the equation:
\[ 3(2x + 2) - x - 3 = -12 \]
- Distribute the \(3\) to the terms inside the parentheses:
\[ 3 \cdot 2x + 3 \cdot 2 - x - 3 = -12 \]
This simplifies to:
\[ 6x + 6 - x - 3 = -12 \]
- Combine like terms (combine \(6\) and \(-3\), and \(6x\) and \(-x\)):
\[ 6x - x + 6 - 3 = -12 \]
This gives:
\[ 5x + 3 = -12 \]
- Now, isolate \(5x\) by subtracting \(3\) from both sides:
\[ 5x = -12 - 3 \]
Which simplifies to:
\[ 5x = -15 \]
- Finally, divide both sides by \(5\):
\[ x = \frac{-15}{5} \]
This simplifies to:
\[ x = -3 \]
So the solution is:
\[ \boxed{-3} \]