Question 114763
find the center and radius for this circle

x^2-4x+y^2+2y=-1
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Complete the square on the x-terms and on the y-terms separately.
x^2-4x + 4 + y^2+2y + 1 = -1+4+1
(x-2)^2 + (y+1)^2 =  4
Center: (2,-1)
Radius: 2
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Cheers,
Stan H.