Strongly recommended
Essence of linear algebra preview
Why people recommend it
Begins 3Blue1Brown's linear algebra series, which engineers credit with providing the geometric intuition behind the matrices and complex numbers used in circuit analysis.
Watch for: pure maths rather than electronics; watch the whole series
In their words
Essence of linear algebra by 3blue1brown: this link is the first of a series of 15 videos, all of which you should carefully watch.
jonk on electronics.stackexchange.com, May 2018. CC BY-SA.
3Blue1Brown's excellent series of (geometric) insights into linear algebra
Buck8pe on electronics.stackexchange.com, Dec 2017. CC BY-SA.