Question

The equation x2 + y2 − 2x + 2y − 1 = 0 is the general form of the equation of a circle. What is the standard form of the equation?

Answer 1

x^2 + y^2 − 2x + 2y − 1 = 0

x^2 − 2x+1-1+ y^2 + 2y+1-1 − 1=0
(x-1)^2+(y+1)^2-3=0
(x-1)^2+(y+1)^2=3
(x-1)^2+(y-(-1))^2=(sqrt3)^2

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