If #x^2+4x+y^2-6y-12=0# is the equation of a circle, what is the length of the radius?

1 Answer
Phillip E.
May 21, 2017

The radius of the circle is 5.

Explanation:

If the equation of the circle is #x^2+4x+y+2-6y-12-0#, first of all need to complete the squares:

#x^2+4x+4 + y^2-6y +9=12+4+9#

This gives:

#(x+2)^2+(y-3)^2=25#

Therefore the centre of the circle is at #(-2,3)# and the radius is #sqrt(25)=5#

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