convert to vertex form
y=x^2-2x-9

i got y=(x-1)^2 - 9, is this right?

Question

convert to vertex form
y=x^2-2x-9

i got y=(x-1)^2 - 9, is this right?

karon86 · Answer

oh thats easy

catlover5925 · Answer

Vertex form is Y = a (x - h)^2 + k
can you solve it now?

karon86 · Answer

okay so translate $$y=ax ^{2}+ bx +c into y=a(x-h)^{2}+k$$

karon86 · Answer

I mean into haha

anonymous · Answer

yeah i know what vertex form, i was jus kinda checking my answer @Catlover5925

karon86 · Answer

y=ax^2+bx+c into y=a(x-h)+k
a=1, b=-2, and c=-9
but you have to find the vertex. (h,k) or (x,y) in this case
in order to find the the x part of the vertex, use the form. $$x=\left(\begin{matrix}-b /\ 2a\end{matrix}\right)$$

karon86 · Answer

so substitute. -(-2)/2(1)

anonymous · Answer

So is my answer right? I do mines a different way by completing the square

karon86 · Answer

So x=2/2 which =1
We just found the x part for the vertex (1,y)
well. In order to find y you have to use that quadratic equation to get y
So y=x^2-2x-9 right?
use that: y=1(1)^2-2(1)-9
y=-10 you just found the y part of the vertex. The vertex is (1,-10) which is (h,k)
plug (h,k) into the y=a(x-h)^2+k 
so y=a(x-1)^2-10
There, But there is one more thing you have to do. You have to plug in a=1
so y=1(x-1)-10. y=(x-1)^2-10 is the answer

karon86 · Answer

Hope this helped. I am glad to help :)

anonymous · Answer

hm i was off by 1. can you double check your answer? i dont want to be wrong, but just want to be sure..
@wio

anonymous · Answer

nvm i understand now