Answer:
The vertex is (-4, -9)
Explanation:
The two roots are located at x = -7 and x = -1, which come from (x + 7) and (x + 1). The axis of symmetry is located halfway between these values, at x = -4. This axis passes through the vertex. The y-value at the vertex is (-4 + 7)(-4 + 1), or -9. The graph is a parabola that opens up. The vertex is (-4, -9).