In this paper, we consider the stability and nonstability results for the following system of functional equations \begin{cases} f(ax_1+bx_2,y,z)+f(ax_1-bx_2,y,z)=2af(x_1,y,z),\\ f(x,ay_1+by_2,z)+f(x,ay_1-by_2,z)=2a^2f(x,y_1,z)+2b^2f(x,y_2,z),\\ f(x,y,az_1+bz_2)+f(x,y,az_1-bz_2)=ab^2(f(x,y,z_1+z_2)+f(x,y,z_1-z_2))+2a(a^2-b^2)f(x,y,z_1) \end{cases} where a, b ∈ Z\{0}, on r-divisible abelian groups.
