Yes, you can answer your own questions. It is even encouraged by Stack Exchange:
It’s also perfectly fine to ask and answer your own question, as long as you pretend you’re on Jeopardy! — phrase it in the form of a question.
It is OK to ask, and answer, your own question on a relevant Stack Exchange site.
To be crystal clear, it is not merely OK to ask and answer your own question, it is explicitly encouraged.
In fact, when you click on the link to ask a question, you will see a checkbox at the bottom giving you the option to answer your own question. Next to the box it says:
Answer your own question – share your knowledge, Q&A-style