I am wondering my self too!
Thank you very much for your answer. The equation was part of a past Algebra examination-test taken at my University, the course is called "Linear Algebra". I am wondering my self, why did they ask such thing (in that course we learn about linear systems, digonalization, eigen values, subspaces, bases etc), how is this equation related to all these topics since it is so easy? Maybe I ask some assistant of the proff some day (the proff him self is too strange he may get mad if I ask him).
Anyway do you mean that the solution is the one I gave? Still wondering why in hell they ask that?
Thank you again my friend, it was kind of you,