Question

How do I find the vertex of the parabola
y=x(squared) + 8x +5

Answer 1

\(-\frac{b}{2a}\) is the first coordinate of the vertex of \(ax^2+bx+c\)
in your case \(a=1,b=8\)

Answer 2

\(\bf \text{vertex of a parabola} \qquad \qquad \left(-\cfrac{b}{2a}, c-\cfrac{b^2}{4a}\right)\)