Vertex form looks like this:
Graphing vertex form
In the equation the -h and k is the points for vertex. When you plot the vertex you would plot in, (h, k). This is because the h turns into a positive when you plot it on the graph and k stays the same. If the h is a positive it would turn into (-h, k). Therefore, when you plot the h value on the graph the signs ALWAYS change. The k never changes signs.
To graph you need to know:
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The step pattern
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The Vertex (value of h and k)
Vertex
Step Pattern
Before you Graph you need to know this
The "a" in the equation tells us the step pattern. When it's a negative the parabola opens down and when it's a positive it opens up. You follow the over 1 , up 1 rule when there's no number in the "a". When there's a number you have to take the coefficient number and multiply it by the step pattern ^2. Example: when the "a" value is -2, then step pattern is over -2, down 8 (you get 8 because (-2 x 2^2) ).
For more information got to the step pattern page.
Vertex: (2,4)
Vertex: (2,4)
There's no "a" value so it's, Over 1, up 1
Over 2, up 4
