Question for guitar players?

The x means you're not meant to play that string, but like you said, it's hard to do that and not touch the strings. The idea is to mute out that sting by lightly touching it (not pressing down hard on the fret board so that you'll get a sound out of it) but try and rest one of your fingers on it and strum. It should be muted out while the rest of the strings are ringing. Hope that helped!