Question

What is the vertex of f(x) = x2 + 10x + 16?
(Points : 2)

(2, 6)


(1, 5)


(5, 9)


(-5, -9)

Answer 1

don't suppose you can take the derivative and set it to zero?

Answer 2

I doubt it, think they're supposed to complete the square

Answer 3

..or use one of those formulas

Answer 4

If you do completing the squares, you'll get it into the form
y=a(x-h)^2+k
where (h,k) is the vertex.
Since h=-5, there's only one choice that matches.
x^2+10x+...=(x+5)^2+...., so h=-5

Answer 5

Thankss mathmate you made mathkid very happy :)

Answer 6

You're welcome! :)

Answer 7

There's really no need to complete the squares. :P\[x^2+10x+16=(x+2)(x+8)\]\(x=-2\) or \(x=-8\).\[\frac{(-8)+(-2)}{2}=-5!\]