Ive forgotten how to find the vertex of a quadratic graph :/

the equation is y=-2(x+2)(x-1)

how you worked it out would be helpful.
"Like a midget at a urinal, I was going to have to stay on my toes"

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I think the variables are h,k other than that i dunno sorry
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i'm a bit rusty, but i think you differentiate it and then find when its equil to 0
there might also be a way by completeing the square, but i can't remember it in enough detail to be any help
The vertex is, I believe, -b/2a. So if you factor that equation out, you've got. -2x^2-2x+4. So, b is -2, and a is also -2. -b/2a + -(-2)/2(-2)

2/-4 = -1/2

Now plug that in as your y variable, and figure out the x. Then you'll have the two coordinates of the vertex.

EDIT: Did anyone actually read TS's post? Or did you all just look at the title?
Look up the vertex formula.

I'm pretty sure they have one.
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Quote by cokeisbetter
The vertex is, I believe, -b/2a. So if you factor that equation out, you've got. -2x^2-2x+4. So, b is -2, and a is also -2. -b/2a + -(-2)/2(-2)

2/-4 = -1/2

Now plug that in as your y variable, and figure out the x. Then you'll have the two coordinates of the vertex.

EDIT: Did anyone actually read TS's post? Or did you all just look at the title?

That equation sounds awfully familiar, I guess I didn't realize it was for the vertex of a quadratic or I might've been able to help
They credited us with the birth of that sort of heavy metal thing. Well, if that's the case, there should be an immediate abortion.

-Ginger Baker
thanx coke...i had already done half of it but using "h" and k(that didnt go so well)...your way seems A LOT easier.
"Like a midget at a urinal, I was going to have to stay on my toes"

"Like a blind man at an orgy, I was going to have to feel my way through"

Quote by YngwieJnr
thanx coke...i had already done half of it but using "h" and k(that didnt go so well)...your way seems A LOT easier.

Luckily for you, it's the only bit of last year's maths that I remember.
x=-.5 and y=4.5
how i figured it out in 3 seconds: