1. **Problem:** Find the domain of the function $f(x) = \frac{2 - 6x}{x + 3}$. The domain consists of all real numbers except where the denominator is zero. 2. **Formula:** The domain restriction comes from the denominator: $x + 3 \neq 0$. 3. **Solve for $x$:** $$x + 3 \neq 0$$ $$x \neq -3$$ 4. **Explanation:** The function is undefined at $x = -3$ because division by zero is undefined. 5. **Final answer:** The domain of $f(x)$ is all real numbers except $x = -3$, or in interval notation: $$(-\infty, -3) \cup (-3, \infty)$$