Question

HELPPP What is the vertex in the quadratic function y = - 4x^2 + 8x - 3 ? Write your answer as an ordered pair.

Answer 1

You have a quadratic in the form

y = ax² + bx + c

so your

a = -4
b = 8

and

c = -3

To find the vertex you use this formula

\[\large Vertex = \frac{ -b }{ 2a }\]

This will give you your x-coordinate..to find you y-coordinate....plug what you get for 'x' in the equation and solve...

Answer 2

-1 ?

Answer 3

is x

Answer 4

Close..

-b/2a so -8/2(-4) = -8/-8 =1 right?

Answer 5

oh yes right.

Answer 6

how would you write the equation to get y

Answer 7

Well now you know that at the vertex...x = 1....so to solve for 'y'...you simply plug in "1" for each 'x' in your equation.

y = -4x² + 8x - 3

after replacing the 'x' with 1...we have

y = -4(1)² + 8(1) - 3

y = ???

Answer 8

21 ?

Answer 9

Not quite...remember you do exponents BEFORE you multiply...

-4(1)² does not mean -4² it means -4 times 1² ....so this simply comes out to -4

so altogther we have

y = -4(1)² + 8(1) - 3
y = -4 + 8 - 3
y = ?

Answer 10

is this right ????

Answer 11

9

Answer 12

I mean 1

Answer 13

Right 1 would be correct...so x = 1 and y = 1...so your ordered pair is

(1 , 1)

Answer 14

Make sense? :)

Answer 15

yessssssss thanksss (:

Answer 16

anytime! :)

Answer 17

What is the vertex in the quadratic function y = x^2 + 8x + 3? Write your answer as an ordered pair. I got this one wrong and don't know what i did wrong

Answer 18

Show me exactly what you did...

remember the equation -b/2a...what do you get for you 'x' coordinate from this?

Answer 19

-4

Answer 20

right....and then you plug that in for the 'x' in you equation so

y = x² + 8x + 3

after plugging it in you get

y = (-4)² + 8(-4) + 3

y = ???

Answer 21

-13 ??

Answer 22

That is correct...you should not have gotten this wrong if what you got was (-4 , -13)

Answer 23

first time i did it i got -45, and i was like that can't be right, its cause I didn't put in the parantheses

Answer 24

Oh okay....yeah just use parenthesis..it makes it easier to follow and you will be less prone to mistakes that way :)

Answer 25

yeah thanks :) so muchh!

Answer 26

like I said...anytime lol :)