We are given this equation

The vertex form is given by:

Now let us try to convert our equation into vertex form:

Vertex form is given by:

comparing our equation with vertex form ,
The vertex (h,k) is (0.5, 2.5)
Next we have to find y when x=6, plugging x as 6 in the given equation,

y=-58
So at x=6, y=-58.