SOLUTION: What is the raius of the circle of x^2+4X+y^2+8y=0

Question 546530: What is the raius of the circle of x^2+4X+y^2+8y=0
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
What is the raius of the circle of x^2+4X+y^2+8y=0
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Standard form of equation for a circle: (x-h)^2+(y-k)^2=r^2, (h,k)=(x,y) coordinates of center, r=radius
..
x^2+4x+y^2+8y=0
complete the square
(x^2+4x+4)+(y^2+8y+16)-4-16=0
(x+2)^2+(y+4)^2=20
This is an equation for a circle with center at (-2,-4)
r^2=20
radius=√20
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