How do I write this equation in standard form? (Conic sections)

x^2 + y^2 - 8x + 10y + 15 = 0

Question

How do I write this equation in standard form? (Conic sections)

x^2 + y^2 - 8x + 10y + 15 = 0

anonymous · Answer

Also, I assume identifying the important features would be the center point, foci, etc.?

anonymous · Answer

i don't know this i'm sorry :(

anonymous · Answer

that's fine lol

potatoes.ramu · Answer

Hey! Try grouping the x, and y terms together to start with :)

anonymous · Answer

Like, grouping them together how? like x^2 - 8x and y^2 + 10y?

potatoes.ramu · Answer

Yup! exactly! Then you'll get an equation that you can compare to the standard form!

anonymous · Answer

I'm not quite sure what the standard form is... I'm looking through my notes because I was sure I wrote it down but apparently not lol

anonymous · Answer

it is a circle

anonymous · Answer

it has a center and a radius, no foci etc

anonymous · Answer

you find it by turning 
$$x^2 + y^2 - 8x + 10y + 15 = 0$$ in to something that looks like 
$$(x-h)^2+(y-k)^2=r^2$$  by completing the square twice 
do you know how to do that?

anonymous · Answer

I've done it before, completing the square, but I think I could use a refresher

jdoe0001 · Answer

@TammisaurusRex  do yo know what a "perfect square trinomial" is?

anonymous · Answer

It's an equation in the form ax^2 + bx + c or something like that, right?

jdoe0001 · Answer

well.. ahemm ---> ax^2 + bx + c   <--- is just a quadratic equation, a 2nd degree equation

jdoe0001 · Answer

http://www.youtube.com/watch?v=xGOQYTo9AKY <---