I think it would be fine next time to just say "hello, nice to see you" and then excuse yourself. Say you have homework, if you want, but you probably don't need to give a reason. Most likely the adults* would rather spend time together, anyway. If they had someone your age coming with them, you might be expected to entertain the other teen.
But these are your parents' friends, so, all that's really expected is a polite hello.
If it's a party or game night and you're expected to join in, you can still excuse yourself to the bathroom if nothing else, sometimes during the event, when you need to chill. At least you can be alone there.
As far as conversation, if you feel you're required to converse, probably say two or three things on a given topic, and then let them take over. Or say one thing and if they don't ask a question, let them take over. If you get no response they're probably not interested in it. (Or they just want to do or talk about something else more.) Boring someone isn't the worst thing in the world, though. It's more about giving them a chance to talk too.
* I realize at 17 you're nearly of legal adult age but, I mean 'the olds' really.