Question

What is the vertex of the quadratic function f(x)=(x-8)(x-2)?

Answer 1

(5, -9)

Explanation:

f(x)=(x-8)(x-2)

We want the vertex. So let us get this in Vertex Form.

f(x) = (x - 8)(x - 2) = x^2 + 16 - 10x

f(x) = x^2 - 10x + 16

f(x) = x^2 -10x + 25 - 25 + 16

f(x) = (x^2 -10x + 25) - 25 + 16

f(x) = (x - 5)^2 - 9

Vertex at (5, -9)