Of the 3 lines you added, the ones that start with # are commented out, ignored by your server. You will need to "toggle" the commented lines, trying each until you find the syntax your server likes.
So if one line doesnt work, add # to the beginning of it to disable it, and remove the # from the next line to try that variation.
Be sure to only have one of the 3 lines un-commented at a time, because that can also cause errors.
Finally, if none of them work, you'll need to contact the people that manage your server. Show them what you have in your .htaccess, and explain that none of the variations work. If they provide another variation that works, please consider coming back and telling us about it
