mm, sorry for the delay. 1)40 books on Linear algebra? You know why? Books on math aren't meant to be read as some literature. THey are hard, and the more abstract, the more value they have, but the harder to read they become. You just need an author which will find a key into your ignorance. They all say same thing (linear algebra), but in different words, that's a key: different wording. You just need to find "your wording".