Focus and Directrix of Parabolic Equations

If a parabola has a focus at (3,0) and a vertex at the origin...what is the equation of the directrix?

• y=3

• y=-3

• x=3

• x=-3

If a parabola has a focus at (0,-3) and a vertex at the origin...what is the equation of the directrix?

• y=3

• y=-3

• x=3

• x=-3

What is the standard equation of a parabola with Vertex (-2, 1) and the directrix is 4 units below the vertex?

If a parabola has a vertex of (1, 0) and a focus of (9/7, 0), what would the fraction be that is in front of the parentheses in the equation?

• 2/7

• 7/8

• 8/7

• 7/2

Which equation below represents a parabola that opens upward?

• y² = -18x

• y² = 16x

• x² = -20y

• x² = 8y

Identify the conic from the equation: y² -4x -2y -2 = 0

• circle

• ellipse

• parabola

• hyperbola

Find the equation of the parabola with vertex (4,6) and focus (4,9).

• (x-4)² = 12(y - 6)

• (x-4)² = 3(y - 6)

• (y-6)² = 3(x-4)

• (y-6)² = 12(x-4)

The focus is a _____ that always lies _______ your parabola.

The directrix is a _______ that always lies ________ your parabola.