Like this one? http://www.gamedev.net/page/resources/_/technical/math-and-physics/math-for-game-developers-intro-to-matrices-r3097

You may want to browse the other math & physics articles too

(I didn't actually watch the article, I know matrices already)

I know most of you have read Programming game ai by examples, so you know that in chapter 3 he uses matrices transformation to rotate his game agent. Unfortunately I'm one of those people who don't know what a matrix is or why did he use a 3x3 matrices? Can anyone share a link or something about matrices and how to rotate a triangle agent just like from the book.

Why do you assume most other users have read that book? I didn't.

3D Matrix Math Demystified by the late Seumas McNally should be a good starting point.

Also, do not expect to find one single short text that covers all you need to know about the subject -- it is a huge one. Consider reading one of the math books aimed at game developers.

I know most of you have read Programming game ai by examples

guess again. try Linear Algebra at The Ohio State University. that's where i learned matrices. and yes, i got an A.