Question

Consider the quadratic function:

f(x) = x2 – 8x – 9



Vertex: (StartFraction negative b Over 2 a EndFraction, f (StartFraction negative b Over 2 a))

What is the vertex of the function?

Answer 1

For f(x) = x^2 − 8x − 9, a = 1 and b = −8.
x-coordinate = −b/(2a) = −(−8)/(2·1) = 4.
f(4) = 4^2 − 8·4 − 9 = 16 − 32 − 9 = −25.

Vertex: (4, −25)