% Script inverse.m

A = [ [1,2,-3,4]; [5,6,-7,8]; [9,8,7,6]; [3,4,5,4] ];
Acopy = A;

[A,r] = gauss(A);
x1 = gaussSolve(A, r, [1,0,0,0]);
x2 = gaussSolve(A, r, [0,1,0,0]);
x3 = gaussSolve(A, r, [0,0,1,0]);
x4 = gaussSolve(A, r, [0,0,0,1]);

Ainv = [x1, x2, x3, x4];

% check

Acopy * Ainv

Ainv * Acopy