How to get my last known location before my tablet went dead. And it is lost

Did you have any kind of tracking service added to it, such as Android Device Manager or a third-party app? If not, then it would be pretty difficult to do. Your service provider might be willing to do a quick search, but that's not guaranteed. It also won't give you a pinpoint location. If you lost it at school, it will show that as the location, but it can't give you the exact spot it's in.