1. **State the problem:** Factor the polynomial expression $4x^3 - 20x^2$ completely. 2. **Identify the greatest common factor (GCF):** Both terms have a factor of $4x^2$. 3. **Factor out the GCF:** $$4x^3 - 20x^2 = 4x^2(x - 5)$$ 4. **Check if the remaining factor can be factored further:** The binomial $(x - 5)$ is already in simplest form. 5. **Final factored form:** $$\boxed{4x^2(x - 5)}$$ This completes the factoring of the given polynomial.