It seems like you have an incomplete equation here. Can you clarify what you would like to do with this expression $4x + x^2 =$? Do you want to solve it for $x$, factor it, or something else?

Let me know, and I'll assist you further!

Do you have any questions or want more details?

Here are 5 related questions:

1. What is the next step if you want to solve a quadratic equation like $4x + x^2 = 0$?
2. How can you factor a quadratic equation like $x^2 + 4x$?
3. What are the different methods for solving quadratic equations?
4. How does the quadratic formula help in solving $x^2 + 4x = 0$?
5. Can a quadratic equation have more than one solution?

Tip: Always check if the equation can be factored easily before using the quadratic formula—it saves time!