find the center and radius of the circle X^2 + y^2 - 8x + 2y = - 1
X^2 + y^2 - 8x + 2y = - 1 'complete the square for x and y
(x-4)^2 + (y+1)^2 = -1 +16 + 1 = 16
(x-4)^2 + ( y+1)^2 = 16
Do you recognize the standard form of a circle equation? center h, k and r^2 are looking right at ya !
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