# How do you find the vertex and axis of symmetry, and then graph the parabola given by: #y= -2x^2#?

##### 1 Answer

Vertex:

Axis of symmetry:

(See below for graph)

#### Explanation:

and be re-written in explicit vertex form as

Any parabola with the form:

has a vertical axis of symmetry (through the vertex)

and opens upward if

Therefore the axis of symmetry for

is

(and opens downward).

Note that

and

so

Therefore it will be necessary to pick a few other values for

#{: (x,,y), (0,,0), (-1,,-2), (+1,,-2), (-2,,-8), (+2,,-8) :}#

By plotting these point-pairs on the Cartesian plane we should be able to sketch the graph for this function.

(Unfortunately, at this time, there seems to be a bug with Socratic.org that prevents posting a graph. I will try to check again later and add the graph if possible).