What is the vertex of the function f (x) = x^2 + 16x?

f (x) = x^2 + 16x

Completing the square.

f (x) = a (x-h) ^2 + k

f (x) = (x + 8) ^2 - 64

h = - 8, k = - 64

Vertex = (h, k)

Vertex = (-8, - 64)

Not fully explained, just a quick summary.