Hey kenny. Upon checking user manual it states that you have to press and hold the Camera button together with press turn on/off. A red screen will be displayed, then the tablet will reset to original factory settings. It wasn't mentioned if the tablet should be turned on or off when doing the process but I would assume it should be turned off. If you don't have a manual yet, you can download it from the Impression 10 product page.
I am tring to factory set my impreeion 10 google play tablet it does not have a camera button on it