Can someone help me beat halo 3 on legrndary on xbox live

I’ll bet you can get tons of help at IGN.com

My understanding is that xbox live is the multiplayer service—it isn’t relevant to beating the campaign mode, which is the only mode with a “legendary” setting.

My advice for beating the campaign on legendary is to be willing to spend a lot of time at it. Just try to make it to the next checkpoint. Generally if you’re willing to find a secure position and let the enemy come to you, and advance slowly, you can make it after several tries. With few exceptions, running through and hoping they don’t take you out before you get to the next checkpoint doesn’t work.

Good luck!