Question

find an equation of the circle with the center (-2,9) and radius 3

Answer 1

x^2 + y^2 + 4x - 18y + 76 = 0

Answer 2

do u want to know how i got this?

Answer 3

(x+2)^2+(y-9)^2=9

Answer 4

yes could you please explain

Answer 5

how did u got this jimmyrep

Answer 6

Multiplied out what I have.

Answer 7

Luis has just done that for me though he has 72 anstead of my 76

Answer 8

If the "moving" part has left any questions, I have used:
\[(x-x_{0})^2+(y-y_{0})^2=R^2\]

Answer 9

is mine right? 85 - 9 = 76

Answer 10

You can move the equacion of a simple Circle:
\[x^2+y^2=R^2\]
Where R -> ray of the circle, and you obtain:
\[(x+2)^2+(y−9)^2=3^2\]
Developing the equation:
\[(x^2+4x+4)+(y^2−18y+81)=9\]
\[x^2+y^2+4x−18y+76=0\]

// Thanks to jimmyrep, i had done it wrong before.

Answer 11

Ok, I get it now! Thank you both so much!!!

Answer 12

yw