Some would say the equation is already in vertex form. For others, you need to subtract 2
y-2 = 1/3(x-1)^2
_____
Where the vertex is (h, k), vertex form shows these values explicitly
y-k = a(x-h)^2
or
y = a(x-h)^2 + k
The first of these forms is the one I learned. It is readily recognized as a translation of
y = ax^2
to a new vertex position.
y-2 = 1/3(x-1)^2
_____
Where the vertex is (h, k), vertex form shows these values explicitly
y-k = a(x-h)^2
or
y = a(x-h)^2 + k
The first of these forms is the one I learned. It is readily recognized as a translation of
y = ax^2
to a new vertex position.