The vertex form of a parabola's equation is generally expressed as :

y=a(x−h)^2+k Where (h,k) is the max or min.

1. Look at the graph.

2. Find the vertex of the graph (h,k)

3. Vertex is the highest / lowest point of the graph known as Max or min (h,K)

Plug this into the form y=a(x−h)^2+k Next solve for "a"

4. To find the "a " ----> pick a point on the graph other than vertex. (usually y intercept)

5. plug it into the vertex form and slove for "a"

IF the general equation is given for the graph: y=ax^2+bx+c, then

1. to find the vertex: use formula x= -b/2a

2. plug x into the given equation to find y value

3. now you have (h,k)

4. find a point on the graph and plug in to the vertex form equation to find "a"

see below for example

y= x^2-2x+3 given: x= -b/2a ------> x= -(-2)/2(1)= 1-----> pug this into the given equation so y= 2

Min (1,2) and now pick x=0 so y=3 (0,3) to find "a"-----> in this case a = 1

y=a(x−h)^2+k

y=(x−1)^2+2