Question

1. If the function fx=x2-2x-15 has roots at the points (-3, 0) and 5, 0, what is the vertex of the function? **

Answer 1

(1, -16)

Explanation:

The line of symmetry is halfway between the x-intercepts, at ...

x = (-3 +5)/2 = 1

The line of symmetry goes through the vertex, so to find the y-coordinate of the vertex, we need to find f(1):

f(1) = 1^2 -2(1) -15 = -16

The vertex of the function is (x, y) = (1, -16).