Question

what are the coordinates of the vertex of the graph of the function y = -x^2 + 6x - 11?
a. (3,-2)
b. (3,16)
c. (-3,-29)
d. (-3,-20)

Answer 1

so \[-x^2+6x-11 \\ =-(x^2-6x)-11 \\ =-(x^2-6x+?)-11+?\]
now what does that one question need to be in order to complete the square

Answer 2

hint:
\[x^2+kx+?=(x+\frac{k}{2})^2 \\ \text{ the } ? \text{ needs to be } (\frac{k}{2})^2\]

Answer 3

so what is you k here?