1. What is the equation of a quadratic function written in intercept form? 2. How do you find the vertex of an equation written in intercept form?

Question

Please help

Answer 1

Hi Tiara.

 

The intercept form for a parabola is:

 

(y - k) = A*(x - h)^2

 

The vertex will be at (h,k)

 

Take the following parabola for example:

 

y = x^2

 

You know from looking at this graph numerous times that the vertex is at the origin. The way this function would be written in intercept form is:

 

y - 0 = 1*(x - 0)^2

 

Vertex is at (0,0) as expected.

 

If we want to make it a little more complicated...

 

y = (x - 4)^2

 

This will be the same parabola, just shifted to the right 4 places.

 

y - 0 = 1*(x - 4)^2

 

Vertex at (4,0)

 

If we again wanted to make it more complicated...

 

y - 2 = (x - 4)^2

 

This will be the original parabola, just shifted to the right 4 spots and shifted up 2 spots.

 

Vertex is at (4,2)

 

Hope this helps.