You are able to delete any answer that you have created or imported into the answer library. The only answers you are not able to delete are your GuideStar answers. This is to avoid accidental deletion.
To delete an answer simply find the answer that you are looking for and click on the red trash can button under the actions section of the answer record.
Once you select this button a pop-up should appear asking you to type DELETE. Once you type this in and hit the delete button the answer will be deleted out of the system.