On the diophantine equation x2-Dy2 = n

We propose a method to determine the solvability of the diophantine equation x(2) - Dy-2 = n for the following two cases: (1) D = pq, where p, q equivalent to 1 mod 4 are distinct primes with (q/p) = 1 and (p/q)(4)(q/p)(4) = -1. (2) D = 2p(1)p(2) ... p(m), where p(i) equivalent to 1 mod 8, 1 <= i <= m are distinct primes and D = r(2) + s(2) with r, s equivalent to +/- 3 mod 8.