Without drawing the graph of the equation, determine how many points the parabola has in common with the x-axis and whether its vertex lies above, on, or below the x-axis.
y = 3x^2 – 12x + 12
2 points in common; vertex above x-axis
2 points in common; vertex below x-axis
no points in common; vertex above x-axis
1 point in common; vertex on x-axis