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

f ( x ) = x 2 − 8 x − 9
Write f ( x ) = x 2 − 8 x − 9 as an equation.
y = x 2 − 8 x − 9
Rewrite the equation in vertex form.
y = ( x − 4 ) 2 − 25
Use the vertex form, y = a ( x − h ) 2 + k , to determine the values of a , h , and k .
a = 1 h = 4 k = − 25