Question

What are the coordinates of the vertex of the graph of the fuction y=-x^2+6x-11?
(3,-2)
(3,16)
(-3,-29)
(-3,-20)

Answer 1

first coordinate is always \(-\frac{b}{2a}\) which in your case is
\[-\frac{6}{2\times (-1)}=3\]

Answer 2

second coordinate is what you get when you replace \(x\) by the first coordinate