% Script ngausstest.m

A = [ [6,-2,2,4]; [12,-8,6,10]; [3,-13,9,3]; [-6,4,1,-18] ];
b = [ 16; 26; -19; -34];

x = ngauss(A,b); % doesn;t change A, b
x

% check with built-in solver

x = A\b

% Check that A*x - b = 0

A*x - b