Row Reduction
= Row Reduction
Section of <Interactive Linear Algebra by Dan Margalit and others> by its whole-book authors <Dan Margalit> and <Joseph Rabinoff>; no separate chapter byline or date is asserted.
Online text: https://textbooks.math.gatech.edu/ila/row-reduction.html
Cited passages: §1.2.1, Augmented Matrices and Row Operations: preservation of solutions; §1.2.2, Echelon Forms: leading entries and reduced form; §1.2.3, definitions of pivot position and pivot column.