A:Answer Sorry to be snarky but, why would you want to?
Chromebooks come with the Chrome browser, a modern browser that is very much in production. Explorer is discontinued, but maintained (see Wikipedia entry). Not to cast aspersions, but IE was known for its quirks and issues. Unless you'd like to import those to a modern computer (and there are, perhaps, reasons why this might be necessary for a few folks), you're better off using almost any other browser. Chrome is a viable candidate.
To be snarky in a different way: you CAN download it, but why would you want to take the next step and INSTALL it?