How do you graph the parabola #y=-x^2-10x-20# using vertex, intercepts and additional points?
1 Answer
Vertex:
3rd point, which is a reflection of the
(See graph at bottom of the explanation)
Explanation:
To find the
In the equation you provided, the corresponding values are:
Plugging in the values to find the vertex yields:
That's the
To find the
Therefore, the vertex is located at the point
To find the
Therefore, the
To find another point, simply draw a vertical line that intersects the vertex. That's called a line of symmetry.
Since you have 2 points, look at the
That point will be your last point, and is located at:
Here is the graph. All the points are correct:
graph{-x^2-10x-20 [-28.97, 22.35, -20.29, 5.35]}