No, you can't post same articles which you have already posted in other sites, even you can't post those articles of your own websites or blogs here. If so then you will violates the copy right rules. Post articles in your own-made words, if you post your own website/blog's articles or your hubpage's articles(as you mentioned above) here then you have to write these in your own words. Don't copy from others' sites. The topic may be same, no problem at all but the contents of that articles should be unique. Because your uniqueness will enrich your popularity as a content writer.
Still have query? Feel free to ask me?