My due date is nov 10 2012 then when I conceive

9 months before roughly... could be 8.5 months or 9.5 months...

If you were sleeping with more than one man around then, you need to DNA testing because you won't know who the father was otherwise

Most likely around February 15. However, conception is just and educated guess with a window of two weeks either way.

As noted, there is no way to tell an exact date and it really does not matter which day. At the best it is give or take a week from the estimated conception date and could be off as much as 2 weeks.

Even the delivery date is a estmated and not exact