We aren't really a solution verification site. It's better to compare notes with a classmate or seek help from a tutor for that type of thing.
What you can do here is try to isolate what you're conceptually unsure of and ask a question specifically about that. You're probably reasonably sure about most steps in your answer, right? It isn't hard to check your calculations line by line. Your lack of certainty probably comes from a particular step where you assumed something or arrived at a conclusion that you're not sure about. Asking a question about that step is generally ok, especially if you generalize it. It may also lead you to a solution before you finish writing it.
You can also ask a question about how to know if you are right. For example, with some elaboration, "How can I verify if I have factored a polynomial correctly?" would be an acceptable question here.