1. **State the problem:** Find the natural domain of the function $f(x) = -\frac{16}{x}$. 2. **Recall the domain rules:** The domain of a function is the set of all real numbers $x$ for which the function is defined. For rational functions like this, the denominator cannot be zero because division by zero is undefined. 3. **Apply the rule:** Set the denominator not equal to zero: $$x \neq 0$$ 4. **Conclusion:** The natural domain of $f(x)$ is all real numbers except $0$. In interval notation, this is $$(-\infty, 0) \cup (0, \infty)$$