Question

Write the equation of the parabola in vertex form
vertex (3,3)
point (1,-9)

This needs to be f(x)= ???

Answer 1

\[f(x) = a(x-h)^{2} +k\]

Answer 2

vertex = (h,k)

Answer 3

so... if you plug in the vertex coordinates given in the template above

how would it look like?

Answer 4

can you help me with a discussion when you are finihed? its the same stuff......:)

Answer 5

sure

Answer 6

thanks :)

Answer 7

f(x)=a(x-3)^2+3?

Answer 8

yep, but you have to find "a"

Answer 9

*hint hint~ plug in points

Answer 10

f(x)=a(1-3)^2+ -9

Answer 11

you will need to plug in the why as f(x)

Answer 12

what? I don't understand how to do that

Answer 13

so you plugged in x, right? Its the same with the y. replace f(x) with -9. so
-9=a(1-3)^2+3

Answer 14

oops....sorry I had put why instead of y....:(

Answer 15

solve for a. so subtract 3 from y first then square that and add to 3 and then divide both sides by that.

Answer 16

-9=a(1-3)^2+3
so i would subtract 3 from outside the parenthesis, which would leave me with -9=a(1-3)^2, right?

Answer 17

it would be-12=a(1-3)^2
-12=a(-2)^2
-12=a(4)
-3=a :) you were close

Answer 18

I kinda worded it wrong at first

Answer 19

so do you know what the end equation is?

Answer 20

so i would put -3(-2)^2+3?

Answer 21

no. it is f(x)=-3(x-3)^2+3

Answer 22

why is it (x-3) instead of (1-3) being simplified to -2... if that makes sense what I'm saying

Answer 23

you don't put the points back in. you just have to revert back to the original equation you can up with: f(x)=a(x-3)^2+3

Answer 24

but you just add the value of a for a.

Answer 25

oh. that makes a little bit of sense, yeah. thank you

Answer 26

:) you're welcome!