Question

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

Answer 1

were you able to get anywhere?

Answer 2

No :/

Answer 3

well first off, you start with this formula

x = -b/(2a)

and this will give you the axis of symmetry

Answer 4

in this case, a = 1, b = -6

so that means


x = -b/(2a)

x = -(-6)/(2*1)

x = ???

Answer 5

x = -3
Not sure. I need a calculator

Answer 6

close, but the two negatives cancel to make a positive

Answer 7

so x = 3

Answer 8

that's the axis of symmetry

Answer 9

aka...the x coordinate of the vertex

Answer 10

plug that x value into the equation to find the y coordinate of the vertex

Answer 11

y=3^2-6(3)+8

Answer 12

to find the y????

Answer 13

yep, keep going

Answer 14

y=9-18+8
y=9-26 ?

Answer 15

-18+8 is NOT -26

Answer 16

Well I kept the sign after 9. So it would be +?

Answer 17

-18+8 is -10

think of it as: you have 18 IOU's, then you pay off 8 of them...so you're left with 10 IOUs

Answer 18

-10

Answer 19

9-18+8

9-10 = ???

Answer 20

-1

Answer 21

so the y coordinate is -1

Answer 22

so what is the final answer?

Answer 23

So I plug all that into the vertex form?

Answer 24

the y coordinate of the vertex I meant to say

Answer 25

yes you do

Answer 26

a = 1 (given)
h = 3 (x coordinate of vertex)
k = -1 (y coordinate of vertex)