When my database is large using x is not that useful (to be honest for some reason it doesn't appear after some number of rows for me).
So, the easiest way I've found is to use firebase cli.
First install it (You need node.js installed) with npm install -g firebase-tools
Login to your firebase project with firebase login.
Remove data with:
firebase database:remove / --project your-project-id
/ here is location of data to delete so for your case you need:
firebase database:remove /locations-orders --project your-project-id