Abstract. We consider the equationover a finite field ކ q of q elements, with variables from arbitrary sets A, B, C, D ⊆ ކ q . The question of solvability of such and more general equations has recently been considered by Hart and Iosevich, who, in particular, prove that iffor some absolute constant C > 0, then above equation has a solution for any λ ∈ ކ * q . Here we show that using bounds of multiplicative character sums allows us to extend the class of sets which satisfy this property.2000 Mathematics Subject Classification. 11L40, 11T30.