**Guide :High School **

# A parabola has its vertex at (2, 2), and the equation of its directrix is y = 2.5. The equation that represents the parabola is .

A parabola has its vertex at (2, 2), and the equation of its directrix is y = 2.5. The equation that represents the parabola is . A) x^2+4x-2y=0 B )x^2+4x+2y=0 C )x^2-4x+2y=0 D) x^2-4x-2y=0**Ok, the standard for I use for this equation is where (h, k) is the vertex and a is the focal length. the focal length is the distance between the vertex and directrix. other things to identify: the directrix is about the vertex so the parabola is concave down ... hence a is negative... so the parabola after substituting the information is which becomes just re-write the equation with everything on the left and match it to the answer choices.**...