[_zax2]

Disclaimer: I have studied linear algebra with your book. Thank you for writing it. Special thanks for making it completely free and open-source.

I have gotten a fair number of emails along the lines of "I'd like to adopt your book but since anyone can download the answers, I cannot teach out of it."

When we had an introductory course in linear algebra, we were not given any home assignments. Instead, we were told that if we want to train and exercise some concepts, we should find third-party materials and self-study -- and so, I used your book. I really like that approach, it allows more capable students to do whatever they like instead, and to less capable -- work on it, if needed. Thus, I don't understand the rationale of not teaching out of something that contains solved exercises, because there is no reason to assign mandatory exercises in the first place. It's enough to have tests.

And of course, such books are extremely valuable for non-mainstream (that is, not enrolled into a high school or wherever) audience, which can be smaller, but has more impact regarding feedback.

[bytematic]

Not all resources are of similar quality and profs aren't going to let the students judge that for themselves. I imagine a prof wants questions that specifically walk students through what they are teaching.