Linear Algebra by Jim Hefferon (free Textbook)

The book, the complete answers to all exercises, classroom presentation slides, and a lab manual using Sage, are all available for download, as well as for purchase. The second edition of Linear Algebra is still available, for someone in a legacy situation: book and answers. (I can’t resist noting that for any widely-available text any college student can get from the Internet copies of the answers.

Source: joshua.smcvt.edu