Question 95
Given $a$, $b$ distinct positive integers, show that the system of equations
$$
xy + zw = a
$$
$$
xz + yw = b
$$
has only finitely many solutions in integers $x$, $y$, $z$, $w$.
$$
xy + zw = a
$$
$$
xz + yw = b
$$
has only finitely many solutions in integers $x$, $y$, $z$, $w$.