 This video is called Practice Problems 4. The instructions say to write and solve an inequality to describe the possible values of X. This is going to be a range problem because you can look and see that we are given a side length of 15, a side length of 22 and a side length of 5X plus 7. We're trying to figure out what could that X be and still make a triangle. So if you look at this triangle right here, you can see that 15 is your smallest side, 22 is your largest side, and the 5X plus 7 would be your medium or middle side. So we'll treat this just like a range problem. Or when you do a range problem to find that number, you know it's going to be bigger than when you subtract your sides, your biggest and your smallest, and it's going to be smaller than when you add them together. So let's go ahead 22 minus 15 is going to be 7, and 22 plus 15 is going to be 27. And then let's replace this middle side with my 5X plus 7. So what I have right here is basically two equations I have to solve. I have two fence problems to do. So to get this X alone, I'm going to subtract 7 from all three sides. So I end up with 0 is less than 5X, which is less than 20. Then to get the X alone, I'll divide everything by 5. So I have 0 is less than X, which is less than 4. So that is telling me that X can be somewhere between 0 and 4 to make this triangle work. So this would be my final answer.