I don’t even know how to start the problem. Can someone help?

Use set buikder notation to represent the following set: {, -2, -1, 0}

()1. how do you find range? 2.the following set of data is to be organized into a histogram. if there are to be five intervals on the graph, what should the length of each interval be? 30, 34, 23, 21, 27, 25, 29, 29, 25, 23, 32, 31

The longer leg of a 30-60-90 trangle is 18