His videos on linear algebra are excellent, but they are not a complete resource. If you want a comprehensive resource, search for the LA course by "maththebeautiful" on YouTube. Also check out Gilbert Strang's MIT lectures.
NB: MathTheBeautiful [1] is by MIT alum Pavel Grinfeld [2]. He approaches Linear Algebra from a geometric perspective as well, but with more emphasis on the mechanics of solving equations. He has a ton of videos organized into several courses, ranging from in-depth Intro to Linear Algebra courses to more advanced courses on PDEs and Tensor Calculus. Highly recommended.
Esp note his video on Legendre polynomials [3] and Why {1,x,x²} Is a Terrible Basis: https://www.youtube.com/watch?v=pYoGYQOXqTk&index=14&list=PL....
[1] MathTheBeautiful https://www.youtube.com/channel/UCr22xikWUK2yUW4YxOKXclQ
I just realized there's a deep connection among your recommendations...Gilbert Strang was Greenfield's PhD advisor: https://dspace.mit.edu/handle/1721.1/29345. Pavel has a clear and precise teaching style like Strang, and I've heard him reference Prof's Strang's courses before but didn't make the connection. Good trees produce good fruit. The small world graph and the truth of that never ceases to amaze. Good trees, good stuff.