Question

Algebra 2 help

Answer 1

using the distance formula solve or help me solve it thanks

Tony is trying to find the equation of a quadratic that has a focus of (−1, 4) and a directrix of y = 8. Describe to Tony your preferred method for deriving the equation. Make sure you use Tony's situation as a model to help him understand.

Answer 2

Are you doing FLVS?

Answer 3

no

Answer 4

Just wondering...
The Distance Formula is --> \[d=\sqrt{(x _{2}-x _{1})^2+(y _{2}-y _{1})^2}\]
First step is to substitute the focus coordinated for \[(x _{1},y _{1})\] -->
\[d=\sqrt{(x _{2}-(-1))^2+(y-4)^2}\]

The directrix y=8, this point will be (x2,y2) --> \[d=\sqrt{(y _{2}+8)^2}\]

Answer 5

I understand that part but once you square everything and then simplify the equation seems to not seem logical

Answer 6

thats where i get confused

Answer 7

nvm thanks for the help i already have it

Answer 8

you must make them equal. --> \[\sqrt{x _{2}-(-1))^2+(y-4)^2}=\sqrt{(y _{2}+8)^2}\]
To get rid of the square root signs it has to be squared. --> \[(x _{2}-4)^2+(y-4)^2= (y _{2}+8)^2\]
Tip leave the 'X' binomials alone, multiply out the y's