Parabolas

A parabola, with its vertex at the origin, has a directrix at y = 3. Which statements about the parabola are true? Check all that apply.

The focus is located at (0, -3) The parabola can be represented by the equation x^2 = -12y

Which graph represents the equation y^2 = -4x?

a. (opens to the left)

A parabola is represented by the equation x^2 = 4y. What are the coordinates of the focus of the parabola?

b. (0, 1)

A general formula for a parabola is y^2 = 4px. What is the value of p in the equation y^2 = -4x?

p = -1

A parabola has a vertex at (0, 0). The focus of the parabola is located at (4, 0). What is the equation of the directrix?

x = -4

The focus of a parabola is located at (4, 0) and the directrix is located at x = -4. Which equation represents the parabola?

d. y^2 = 16x

A parabola has a vertex at (0,0). The focus of the parabola is located on the positive y-axis. In which direction must the parabola open?

a. up

A parabola has a vertex at (0,0). The focus of the parabola is located on the positive x-axis. Which part of the graph will be the directrix pass through?

b. the negative part of the x-axis

A parabola has a vertex at the origin. The equation of the directrix of the parabola is y = 3. What are the coordinates of its focus?

c. (0, -3)

A parabola has a vertex at (0, 0). The equation for the directrix of the parabola is x = -4. In which direction does the parabola open?

c. right

A parabola is represented by the equation y^2 = 5x. Which equation represents the directrix?

d. x = -5/4

The focus of a parabola is located at (0, -2). The directrix of the parabola is represented by y = 2. Which equation represents the parabola?

d. x^2 = -8y

Which equation represents the parabola shown on the graph? (0, 15)

d. x^2 = 6y