can I delete back up files on MacBook Air?.

Bought iPhone 7 plus two months ago. In-store Installed iPhone from MacBook Air back up. Have previously always backed up on MacBook Air. Now I want to back up new iPhone, but MacBook Air (capacity of 500 GB) says not enough space. I checked the library "backups" And found three large folders (77 GB, 41 GB and 0 bytes (last one with date I tried backing new iPhone up and got "not enough memory/storage" I am guessing they are old back ups of my previous iPhone. So I should be able to delete them, correct? Then I'll have space to do new back up. If I am correct, how do I delete these three files? Thanks!!!