a b s t r a c t
In this study, we investigate positive integer solutions of the Diophantine equations x2 −
kxy∓y2∓x = 0 and x2−kxy−y2∓y = 0. It is shown that when k > 3, x2−kxy+y2+x = 0
has no positive integer solutions but the equation x2 − kxy + y2 − x = 0 has positive
integer solutions. Moreover, it is shown that the equations x2 − kxy − y2 ∓ x = 0 and
x2 − kxy − y2 ∓ y = 0 have positive solutions when k ≥ 1.
© 2010 Elsevier Ltd. All rights reserved.