Question

What is the vertex of the quadratic function?

х) = (х – 8)(х – 4)
А. (-6,4)
В. (6-4)
с. (-4,8)
D. (4,8)

Answer 1

The vertex is (6, -4)

Explanation:

f(x) =(х – 8)(х – 4)

First find the zeros

0 = (х – 8)(х – 4)

0 = x-8 0 =x-4

x=8 x=4

The zeros are x=8 and x=4

The vertex is 1/2 way between the zeros

(8+4)/2 = 12/2 =6

To find the y value, substitute 6 into the function

f(6) = (6-8) (6-4)

= -2 (2) = -4

The vertex is (6, -4)