Add Linear Algebra Textbook (#9153)

more/free-programming-interactive-tutorials-en.md

@@ -125,6 +125,7 @@
 * [Data Science Foundations](https://skillsbuild.org/students/course-catalog/data-science) - IBM SkillBuild *(email address required)*
 * [Data Science Tutorial](https://www.w3schools.com/datascience/default.asp) - W3Schools
 * [Essential Linear Algebra for Data Science and Machine Learning](https://www.kdnuggets.com/2021/05/essential-linear-algebra-data-science-machine-learning.html) - KDnuggets
+* [Interactive Linear Algebra](https://textbooks.math.gatech.edu/ila/) - Dan Margalit, Joseph Rabinoff (HTML, PDF)
 * [Top 10 Data Science Projects for Beginners - KDnuggets](https://www.kdnuggets.com/2021/06/top-10-data-science-projects-beginners.html)