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?

(x − 1)2 − (y − 1)2 = 1

(x − 1)2 + (y + 1)2 = 3

(x + 1)2 + (y − 1)2 = 1

(x − 1)2 + (y + 1)2 = 1