Question

can you help me with this!! true or false the vertex of y=9-8x-x2 is (-4,25)

Answer 1

parabola vertex form is:\[y=a(x-h)^{2}+k\]
where (h,k) is the vertex.
So just put your equation in this form by compleating the square and you will get the answer

Answer 2

another way to do it is to use \(\large x=-\frac{b}{2a} \) as the x-coordinate of your vertex. to find the y-value just plug that into your expression.