The radius of the circle represented by equation 3x2 + 3y2 + λxy + 9x + (λ – 6) y + 3 = 0 is

Given that the equation of the circle is:


3x2 + 3y2 + λxy + 9x + (λ - 6)y + 3 = 0 ...... (1)


Comparing with the standard equation of circle:


x2 + y2 + 2ax + 2by + c = 0


We get


λ = 0


Substituting λ value in (1), we get


3x2 + 3y2 + 0xy + 9x + (0 - 6)y + 3 = 0


3x2 + 3y2 + 9x - 6y + 3 = 0


x2 + y2 + 3x - 2y + 1 = 0


We know that for a circle x2 + y2 + 2ax + 2by + c = 0


Centre = (- a, - b)


Radius =


Radius (r) =





The correct option is (a)

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