Welcome to Android Central! How do you know they're draining your battery? Do they show up in the Settings>Battery menu as using a lot of battery? Apps that are open in RAM but not in the foreground usually don't use any battery at all, since they're essentially on "pause." Manually closing apps doesn't always help, because the system may reopen the app automatically (Android always wants RAM relatively full, not like Windows).
If you never use the app, either uninstall it (if it's a 3rd party app) or disable it (if it's preinstalled and can't be removed).