Hyers-Ulam Stability of Functional Equationf(3x) = 4f(3x − 3) + f(3x − 6) Year: 2010 Volume: 4 Issue: 2 302 - 305 Pages Authors: Soon-Mo Jung Abstract: The functional equation f(3x) = 4f(3x-3)+f(3x- 6) will be solved and its Hyers-Ulam stability will be also investigated in the class of functions f : R → X, where X is a real Banach space. Keywords: Functional equation Lucas sequence of the first kind Hyers-Ulam stability.