Find all possible pairs of positive integers (x,y) such that both x²+5y and y²+5x are perfect squares.
I would like to congratulate Charlie and Eric for their solution of this problem by their respective methodologies which are precise and accurate in all respects.
While on the subject, I would also like to acknowledge the various posts of e.g. in this respect who made a very nice effort at solving a complex problem at the outset, without the benefit of any hint/tips.
Acknowledgements
