Answer:
Axis of symmetry: x=-4
Explanation:
If x=-7 and x=-1 are solutions to a quadratic equation, then that quadratic equation must be (x+1)(x+7)=0 -> x^2+8x+7=0 as both solutions satisfy the Zero Product Property where the function is f(x)=x^2+8x+7. The axis of symmetry would be the line x=-b/2a which means the axis of symmetry is x=-(8)/2(1)=-8/2=-4 -> x=-4. It can also be found by turning f(x)=x^2+8x+7 into f(x)=(x+4)^2-9 by completing the square, and since h=-4, then the axis of symmetry would be x=h=-4. Refer to the graph.