Given expression for function :
[tex]f(x)=x^2+6x+8[/tex]The general form of equation is :
[tex]ax^2+bx+c=0[/tex]The axis of symmetry is define as : the line that divides the parabola into two equal halves,
i,e
[tex]\text{ Ax is of symmetry = }\frac{-b}{2a}[/tex]From the given expression we have a= 1, b =6, c=8
So,
Axis of symmtery = -6/2(1)
Axis of Symmetry = -3
i.e x = -3
Now for the vertex
Vertex : which is the minimum point of the parabola and the parabola opens upward.
for vertex
Substitute the x = -3 and solve for the valur of f(x)
[tex]\begin{gathered} f(x)=x^2+6x+8 \\ f(-3)=(-3)^2+6(-3)+8 \\ f(-3)=9-18+8 \\ f(-3)=-9+8 \\ f(-3)=-1 \end{gathered}[/tex]So the vertex will be (-3, -1)