Question 137
a) Prove that there are no odd numbers $x, y, z$ such that $xy+1, yz+1, zx+1$ are all perfect squares.
b) Prove that there are infinitely many even numbers $x, y, z$ such that $xy+1, yz+1, zx+1$ are all perfect squares.
b) Prove that there are infinitely many even numbers $x, y, z$ such that $xy+1, yz+1, zx+1$ are all perfect squares.