Nina knows that the average of the x-intercepts represents the line of symmetry for a quadratic function through the x-axis. Which equation represents the average of the x-intercepts for f (x) = 4x2 - 24x + 20?

-5-1/2 = - 3

-10-2/2 = - 4

1+5/2 = 3

2+10/2 = 4

To get the x-intercepts of the function, f (x) = 4x2 - 24x + 20

It has to be equated to zero and the values of x are the x-intercepts. So,

4x2 - 24x + 20 = 0

The resulting equation is a quadratic equation which can be solved by different methods. The solution is

x = 5, 1

The average therefore is:

(1+5/) 2 = 3