Write the equation of the parabola in vertex form.

y = -(x - 2)^2.

Step-by-step explanation:

Vertex form is a(x - b)^2 + c   where  a is a constant and (b, c) is the vertex.

Here b = 2 and c = 0

So we have:

y = a( x - 2)^2 + 0

When x = 4 y = -4 so:

-4 = a( 4 - 2)^2

a = -4/2^2 = -1

So the required equation is

y = -(x - 2)^2.