(1) Since the eigen values of u1 and u2 are not equal, their directions are different, so u1 and u2 are not parallel.
(2) Set the eigenvalue of u1, u2 respectively for λ1, λ2, then the eigenvalue of u1+u2 for λ1+λ2, because λ1≠λ2, so u1+u2 is not the eigenvector.