Q: i would like to lose about 120 lbs in 6 months is this possible

A: It's almost certainly impossible and even if it was possible it would be a bad idea. Weight loss at a fast pace like this (nearly 5 pounds/week) would destroy a lot of your muscle mass in addition to fat. That's very bad for a couple of reasons (even forgetting about basic health reasons for a moment). First, your muscle is the biggest thing that allows you to burn fat effectively in the first place, so the more muscle you lose the less fat you'll be able to burn. After a month or two of a crash diet like this your weight loss will come to a halt and leave you without much fat-burning muscle but still with plenty of fat. Second, the same muscle mass is your best protection against future fat gains, so by destroying your muscle mass you're making yourself very vulnerable to new fat gains in the future. Both these reasons are why crash diets almost always fail.

Instead of trying to lose a lot of fat so fast, you should realize that it didn't get this way in just 6 months so there's no way you can expect it to disappear in just 6 months either. Take your time and aim for 2 pounds/week weight loss. A steady weight loss like that will preserve your muscle mass and allow you to lose fat for a long long time. Please read this article for a detailed advice about how to proceed on this program. Good luck!