1. **State the problem:** We are given a profit function $p(x) = 2x - 500$, where $x$ is the number of units sold. We need to find the profit when 300 units are sold. 2. **Formula used:** The profit function is $p(x) = 2x - 500$. 3. **Substitute the value:** To find the profit when $x = 300$, substitute 300 into the function: $$p(300) = 2(300) - 500$$ 4. **Calculate:** $$p(300) = 600 - 500 = 100$$ 5. **Interpretation:** The profit when 300 units are sold is 100.