This is a very long and long-winded derivation of the formula to solve any cubic equation. Not sure who this is for exactly since there are shorter and perhaps better explanations out there, but I tried to explain and motivate every step. In particular, I tried to motivate and explain converting a general cubic into a depressed cubic and make that seem like a reasonable thing to do.
I followed the logic of https://loopspace.mathforge.org/CountingOnMyFingers/CubicFootsteps/
So perhaps go read that instead. If you found yourself wondering aloud at every step "why did he do that?" or "how did he know to do that?" then watch my video.
10/29/2020
