Question: find all real zeros of $f$
1. **State the problem:** We need to find all real zeros of the function $f$, which means solving the equation $f(x) = 0$ for real values of $x$.
2. **Formula and rules:** To find zeros of a function, set the function equal to zero and solve for $x$.
3. **Intermediate work:** Since the function $f$ is not explicitly given, please provide the expression for $f(x)$ so we can proceed with solving $f(x) = 0$.
4. **Explanation:** Finding zeros means finding where the graph of $f$ crosses the $x$-axis.
5. **Final answer:** Cannot determine without the explicit function $f(x)$.