From vertices and co-vertices to foci and eccentricity, this video hits the basics. https://youtu.be/4Epr-QPWF3g?si=vWikeu38qmx_dMee

https://youtu.be/uca8GAUykdM?si=PhzzM4bwYFqrNYiC See how the fundamental theorem of algebra and the factor theorem work together.