Check out Linear Algebra: Foundations to Frontiers (https://www.edx.org/course/linear-algebra-foundations-fronti...), it's being offered self paced by edx, and you can download the lecture notes for free at http://www.ulaff.net. When I took the course two years ago I liked how the lecturer will discuss basic concepts in the lectures but also gives additional material related to state of the art research being done in the field.

There also used to be a course called Coding the Matrix, I'm not sure if it is still being offered online. The lecture notes form a book of the same title, which is available for less than 10$ (Kindle).

Yeah, part of my motivation for doing a lot of maths study is exactly that I took that Andrew Ng class. You can get through the class without knowing multi-variable calculus and linear algebra and what-not, but that class made it clear to me that learning that stuff would be hugely beneficial.