Question

If equation of Circle B is x^2 + y^2 - 4x +12y - 7= 0, find the center and the radius of circle B. Center = (_,_), Radius =

Answer 1

@3mar

Answer 2

Well, I am here.
That is with my pleasure to help you!

Answer 3

Thank you!

Answer 4

Not at all!

Are you familiar with circle equation?

Answer 5

No I didn't know the formula, thanks for telling me

Answer 6

So can you deal with it?

Answer 7

Eh, its confusing because I'm not sure whether I'm suppose to plug in the numbers

Answer 8

Are you familiar with completing a square?

Answer 9

Yes.

Answer 10

Great!
Can you do that for this x and y in that relation (x^2 + y^2 - 4x +12y - 7= 0)??

Answer 11

x^2 - 4x ??????

y^2 + 2y ??????

Answer 12

Yeah, sorry for the long reply. I did (x^2 - 4x) (y^2 + 2y) - 7 = 0

Answer 13

No No No No
Not multiplication!

I said : complete the square!!!

Answer 14

I didn't multiply. Now I'm lost

Answer 15

Looks as tho' Juanilet might benefit from your going thru an example of completing the square.

Answer 16

Look!
\[\Large x^2 + y^2 - 4x +12y - 7= 0\]
\[\Large (x^2-4x) + (y^2+12y) - 7= 0\]
\[\Large (x^2-4x\color{red}{+4-4}) + (y^2+12y\color{red}{+36-36}) - 7= 0\]
\[\Large ([x^2-4x+4]-4) + ([y^2+12y+36]-36) - 7= 0\]
\[\Large ([x-2]^2-4) + ([y+6]^2-36) - 7= 0\]
\[\Large [x-2]^2 + [y+6]^2-36 - 7-4= 0\]
\[\Large [x-2]^2 + [y+6]^2-47= 0\]
\[\Large [x-2]^2 + [y+6]^2= 47\]

I hope that helps!

Answer 17

Okay thank you!

Answer 18

Are you satisfied?

Answer 19

A little I'm just dumb.

Answer 20

Why?
I need you 100 % sure!

Answer 21

about completing the square or center and radius of the circle?

Answer 22

@Juanilet2000
Do you follow?

Answer 23

I understand the completing the square I'm just confused on the radius of the circle.

Answer 24

\[\Huge\color{green}ツ\]