A parabola and its focus are shown on the graph. The vertex of the parabola is at (0,0).What is the equation of the directrix of the parabola?y = 3y = –3x = 3x = –3

x= -3

Here's why: The directrix always goes behind the vertext of the parabola (thus the -3), and follows the curve (this parabola demands a vertical line, and we know x=a number creates a vertical line on a graph).