Stop lying to people!
Nobody can understand how Facebook algorithm works! (except if you’re working at Facebook) Because first, No one really knows its real algorithm formula as Facebook is always tweaking it. Second, the News Feed is acting with a lot of prediction and the result could not be exact at 100%. Third, as a marketer, even if you know pretty well your audience and what they really want from you, you will suffer to reach them all! Why? The answer is easy peasy and I guess you know already that because Facebook wants you to pay to reach them.
Like what I did, you’ve probably searched on Google to understand more what does this weird “EdgeRank” mean, and you’ve got certainly thousands of articles like: “How Facebook algorithm works”, “7 easy tips to increase your Facebook algorithm” or “Facebook algorithm revealed: How to remain visible in the cluttered news feed”