function x = ex5(A, B, b, n)

%input check
if ~(n >= 4 || ismatrix(A) && ismatrix(B) && size(A) == size(B) && size(A,1) == size(A,2))
    error('Invalid input')
end
m = size(A, 1); %rows and cols
Aextended = kron(eye(n), A);
Bextended = [zeros((n-1)*m, m), kron(eye(n-1), B'); zeros(m, n*m)];
P = Aextended + Bextended + Bextended';
y = repmat(b', 1, n).*repelem(1:n, m);
z = repmat(y, 1, m)';
Q = kron(A,P);
x = Q\z;

end