Find the value of K such that the equation X^2+Y^2+6x-10y+K=0 represents a circle with a radius of 5.

Question

amistre64 · Answer

(x^2 +6x) + (y^2 -10y) +K= 0

Complete the squares of your x and y:

(x^2 +6x +a) + (y^2 -10y +b)  = 0; K= a+b

(x^2 +6x +(6/2)^2) + (y^2 -10y +(10/2)^2)  = 0

K = 3 + 5 = 8

If I remember it correctly :)

anonymous · Answer

Thank you!

amistre64 · Answer

I would need to double check that to be sure if I am right..

amistre64 · Answer

I was close.  K needs to equal (3)^2+(5)^2 = 9+25 = 34.  And the radius of 5 would equal (5)^2 = 25.  K=34-25 = 11 is the correct answer.

anonymous · Answer

Thank you very much!

amistre64 · Answer

Dont thank me yet, I forgot how to subtract :)  34-25 = 9.  Lets go with that :)

anonymous · Answer

I hope I can thank you now.
THANK YOU!

amistre64 · Answer

Yep, that one works.  Youre Welcome :)