What does the letter x represent?

My dear dear friend x can mean anything like X can be a symbol that stands for delete it X can stand for XXX yk also X can stand for a variable X can be a unknown number X can be a letter X can be me cause u want to delete myself outta this world but ya the most educational answer is it’s a variable in math but idk why u would be asking it in the social studies section

3. i would say one, but one is not prime nor composite.