How should I reference my own previous work in a talk to a general audience?
If the list of authors is short, just write all of them:
For example: Lagrange, Cauchy and Carnot, 1800, Journal of Mathematics
You may want to put your own name in bold.
If there are many authors, then a pretty standard way in many disciplines is to write as FirstName et al., see here: https://www.scribendi.com/advice/how_to_use_et_al.en.html 
But if you are at the middle, you need to choose. Maybe something link:  AAA ... YouName et al., 
Or you can still put your name as first and the rest as et al.,