# How do you find the standard form of the equation Vertex: ( -1, 2), Focus (-1, 0) Vertex: (-2, 1), Directrix: x = 1?

##### 1 Answer

Oct 2, 2017

Use the fact that a parabola is the locus of points equidistant from the focus point and the directrix line.

#### Explanation:

The distance from the directrix,

The distance from the focus,

Simplify:

Because the distances must be equal, we can set the right side of equation [1] equal to the right side of equation [2]:

Square both sides:

Expand the squares:

Combine like terms:

Divide both sides by -4: