## ehamer 2 years ago x2 + y2 + 10y + 20 = 0

1. zzr0ck3r

whats the question?

2. ehamer

Show that the equation represents a circle by rewriting it in standard form, and find the center and radius of the circle.

3. Azteck

complete the square for y.

4. matricked

x^2 +(y+5)^2= 5

5. Azteck

good work matricked, no working whatsoever to show how you got that.

6. matricked

centre (0,-5) and radius sqrt(5)

7. manishsatywali

|dw:1359616706864:dw|

8. ehamer

THanks! makes sense now!

9. manishsatywali

compare this with equation of circle (x-a)^2 + (y-b)^2 = r where a,b is the centre and r is the radius

10. manishsatywali

so a = 0 y = -5 r=$\sqrt{5}$