f x 4x 8x Does the parabola defined by f open upward or downward Downward Upward Determine the vertex in x y form of the parabola defined by f Determine the y intercept in x y form of the parabola defined by f Determine the x intercept s in x y form of the parabola defined by f If multiple x intercepts exist enter the solutions using a comma separated list If no x intercepts exist enter DNE Determine the axis of symmetry of the parabola defined by f