The equation x squared + y squared − 2x + 2y − 1 = 0 is the general form of the equation of a circle. What is the standard form of the equation? (x − 1)squared - (y − 1)squared = 1 (x − 1)squared + (y + 1)squared = 3 (x + 1)squared + (y − 1)squared = 1 (x − 1)squared + (y + 1)squared = 1