When your looking at the rear of the notebook there is a line of copper terminals which ones or positive and which ones are negative usually are marked with a plus and a minus but this one is not
If you are looking for a new charger, just look at the markings on your old charger.
If you are looking at the battery terminals, don't mess with them. Not all are for power.
You can just use a multimeter on the battery terminals to check the terminals you suspect as the power ones.