So let me write this down. x is going to be greater than or equal to zero. And what does it have to be less than? Well, I can cut at most, we can see here the length right over here, this pink color, this mauve color, is 20 minus two x. So this has got to be greater than zero. This is always going to be shorter than the 30 minus two x. But the 20 minus two x has to be greater than or equal to zero.