I put in an answer to a question, but while I was writing/researching the answer, the question changed to include my answer, So it now looks like my answer is complete rubbish and I'm getting down votes.
How can I delete this answer?
You should be able to delete any answer you've created, as long as it hasn't been accepted by the question asker. I've included a screen shot (complete with free-hand circle) from a site where I have lower reputation, to verify that you shouldn't need a certain reputation amount to delete your own answer:
For more information, this meta post covers this topic.