what is the vertex form of the equation?
y=x^2-6x+8?

Question

what is the vertex form of the equation? 
y=x^2-6x+8?

anonymous · Answer

@jdoe0001 help?

jdoe0001 · Answer

http://www.mathwarehouse.com/geometry/parabola/images/standard-vertex-forms.png

jdoe0001 · Answer

now, you just need to factor it to reflect the "vertex form", then from that use (h,k) :)

anonymous · Answer

wait so I basically just plud in the problem? im confused ha

jdoe0001 · Answer

one sec

anonymous · Answer

ok

jdoe0001 · Answer

first off, you need to get a squared binomial, for the vertex form, the way to do it, is to get a perfect trinomial from it firstly

anonymous · Answer

how do i do that,,

jdoe0001 · Answer

$$x^2-6x+8\ = x^2-6x+8+(1-1) $$
so basically, we're using "0", (1-1), to try to make "8" to 9, since $$\sqrt{9}=3$$

jdoe0001 · Answer

remember that a perfect trinomial is
$$A^2+2(AB)+B^2$$

anonymous · Answer

okay.. i think i get it a little i guess... i was just skipped a class and put into this one so its really difficult

jdoe0001 · Answer

so in this case, we have A^2=(x^2), 2(AB)=(-6x), and B=(8), but 8 doesn't have a rational root, thus the padding of it using +1 to make it 9 and 9 does have a rational root, "3"

jdoe0001 · Answer

$$x^2-6x+8\ =\  x^2-6x+8+(1-1)$$
$$=x^2-6x+9-1$$
$$=(x^2-6x+9)-1$$

jdoe0001 · Answer

$$=(x^2-6x+9)\ = \ ?$$

anonymous · Answer

hmmm would it be 6x^2+9

jdoe0001 · Answer

remember that a perfect trinomial is
$$A^2+2(AB)+B^2$$

jdoe0001 · Answer

and from there you can get a binomial to the 2nd power

jdoe0001 · Answer

which is what you need for the vertex form

anonymous · Answer

oops...so haha i still dont really get it :/ im trying i swear!

jdoe0001 · Answer

http://neaportal.k12.ar.us/wp-content/uploads/2010/09/la1a16_simplify-expressions-by-factoring_difference-of-squares_perfect-square-trinomial.jpg

jdoe0001 · Answer

holy smokes!, that example is identical to yours :)

anonymous · Answer

haha. I was gonna say! you went through all that trouble to make me something i would understand ;) but thank you!

jdoe0001 · Answer

anyhow, once you group those 3 terms into the binomail, you'd be left with the (-1), put them together and that's your vertex form, from there you get the (h,k) :)

anonymous · Answer

okay okay so i plug it into the y=a(x-h)^2+k?

jdoe0001 · Answer

well, group those 3, to make squared binomial, what does the equation look like after that?

jdoe0001 · Answer

still confused?