Question

What is the vertex form of `y=x^2+9x+28`?

Answer 1

Vertex form of equation is `y = (x +4.5)^2 + 7.75`

Explanation:

`y = x^2 + 9 x +28` or

`y = (x^2+ 9 x +4.5^2) - 4.5^2+ 28` or

`y = (x +4.5)^2 - 20.25+ 28` or

`y = (x +4.5)^2 + 7.75` Comparing with vertex form of

equation `f(x) = a(x-h)^2+k ; (h,k)` being vertex we find

here `h= -4.5 , k=7.75 :.` Vertex is at `( -4.5,7.75)`

and vertex form of equation is `y = (x +4.5)^2 + 7.75`

graph{x^2+9 x+28 [-35.56, 35.56, -17.78, 17.78]} [Ans]