Gaussian Elimination: Matlab

function [x] = gausselim(a,b)
%GAUSSELIM a on the left, b on the right.
a = [a b];
for k = 1:length(a)-2 %Column from 1 to third last
    for i = k+1:length(a)-1 %row from k+1 to second last
        r = a(i,k)/a(k,k);
        for j = k:length(a) %column from k to last, subtraction
            if a(i,j)
                a(i,j) = a(i,j) - a(k,j)*r;
            end
        end
    end
end
%Solving phase
x = zeros(length(a)-1,1);
for i = length(a)-1:-1:1
    for j = i:length(a)-2
        a(i,end) = a(i,end) - a(i,j+1)*x(j+1);
    end
    x(i) = a(i,end)/a(i,i);
end