function C = assign3(A,B)
A = [1 1 -2 1 3 -1;2 -1 1 2 1 -3; 1 3 -3 -1 2 1;5 2 -1 -1 2 1;-3 -1 2 3 1 3;4 3 1 -6 -3 -2];
B =[4;20;-15;-3;16;-27];
    i = 1;
    X = [ A B ];
    [ m n ] = size( X);
    while i <= m
        if X(i,i) == 0
            disp('Diagonal element zero')
            return
        end
        X = elimination(X,i,i);
        i = i +1;
    end
    C = X(:,n);
function X = elimination(X,i,j)
[ m n ] = size( X);
a = X(i,j);
X(i,:) = X(i,:)/a;
for k =  1:m
    if k == i
        continue
    end
    X(k,:) = X(k,:) - X(i,:)*X(k,j);
end
ans =

            1
           -2
            3
            4
            2
           -1