Question

What is the vertex of the quadratic function f(x) = (x - 6)(x + 2)?

Answer 1

The vertex is (2,-16)

Explanation:

We know that the vertex is 1/2 way between the zeros

f(x) = (x - 6)(x + 2)

0 = (x-6) (x+2)

x-6 = 0 x+2 =0

The zeros are at 6 and -2

(6+-2)/2 = 4/2 = 2

The x coordinate of the vertex is at x=2

To find the y value substitute into the equation

f(x) = (2 - 6)(2 + 2)

= -4 *4

= -16

The vertex is (2,-16)