Warning: this is an htmlized version!
The original is here, and
the conversion rules are here. 
/*
 * This file:
 *   http://anggtwu.net/MAXIMA/2025-baf-strang.mac.html
 *   http://anggtwu.net/MAXIMA/2025-baf-strang.mac
 *          (find-angg "MAXIMA/2025-baf-strang.mac")
 * Author: Eduardo Ochs <eduardoochs@gmail.com>
 *
 * (defun e () (interactive) (find-angg "MAXIMA/2025-baf-strang.mac"))
 * (find-books "__alg/__alg.el" "strang" "3" "That singular case")
 * (bafp 14 "solving-equations")
 * (bafa    "solving-equations")
 * (find-Maxima3-links)
*/

linenum:0;
/* block strang by hand */
eq1 : 1*x + 2*y = 3;
eq2 : 4*x + 5*y = 6;
eq3 :         4*eq1;
eq4 :  expand(4*eq1);
eq5 : eq2 - eq4;
eq6 : eq5 / -3;
eq7 : subst(eq6, eq1);
eq8 : eq7 - 4;

linenum:0;
/* block strang by solve */
eq1 : 1*x + 2*y = 3;
eq2 : 4*x + 5*y = 6;
solve([eq1,eq2],[x,y]);