Most of these answers are largely on target. But let's put it all together and be very clear. The content you write is legally yours (you have the copyright, even if you don't formally declare it) and you can publish it where you like. But HubPages has very clear rules against duplicate content, so the hubs you publish on HubPages must not contain passages you publish elsewhere on the web, or they will be flagged as duplicate content, and a violation of HubPages rules.
There is one big exception to this. If you create a video, then all the content of the video (images, sounds, written or spoken words) can be present both in a hub and also as a video posted elsewhere (such as YouTube or Vimeo). This is true both for a video hub and also for a video capsule inside a hub. (I confirmed this with HubPages staff recently.)