The graph of f(x) and table for g(x) = f(kx) are given.
 The graph shows an upward opening parabola labeled f of x that passes through a point negative 2 comma 8, a point negative 1 comma 2, a vertex 0 comma 0, a point 1 comma 2, and a point 2 comma 8.
 x g(x)
 −16 8
 −8 2
 0 0
 8 2
 16 8
 What is the value of k?