Have been exploring a roundabout solution to a linear Diophantine equation:
$$36x^2y^2+ a^2-2bxy-25(x^2+y^2)=0$$ $$x,y\in\Bbb Z; \qquad0 < x,y$$
where a, b are known positive integers.
Considering the example of:
$$36x^2y^2+ 646^2-7802xy-25(x^2+y^2)=0$$ What is the best approach?