There are several different optical drives that can be supplied with this model, however, given the recent age of this model it should have capabilities for both plus and minus formats. I have a 3 year old Dell Dimension desktop and it came with a plus/minus DVD burner standard.
Here is the description of the different DVD types, that I got from the local newspaper about two years ago:
DVD-R and DVD-RW. The first recordable format, allows users to write to a disc only once. The DVD-RW feature allows for re-writes but to play the discs on a standard DVD player or a computer, the disc must be finalized, meaning it can't be recorded to again.
DVD+R and DVD+RW. The most recently developed formats are the +R and +RW. The plus sign indicates the recordings on +R or +RW discs do not have to be finalized before viewing. You can write over what you've recorded or watch an already recorded disc and add more to it later.