“…When q ¼ 2 and m is an odd integer, Cohn [3] has proved that this equation has exactly three families of solutions. When q ¼ 3 and m is an odd integer, Arif and Abu Muriefah [1] proved that this equation has one family of solutions and recently Luca [5] has shown the existence of exactly one family of solutions when q ¼ 3 and m is an even integer. In this paper, we study this equation when q is an odd prime and m; n are odd integers.…”