Playing golf with clients is one way to 'mix business with pleasure'. [=to do something enjoyable that is related to your work]
I accidentally 'mixed up' the two files. [=I put each of the files in the place where the other one should have gone]
He 'got mixed up in' a plan to destroy the government. [=he became involved in a plan to destroy the government]
(..) Not in this tale, dear. - I 't against the official said. Do that. This whole parade is a fiasco. Let's see what this thing can. What are you doing? Then we mix in traffic. Without falling down. And once the 't airport, then nobody more against us. Stop security. (..)2007 Bee Movie