A. (x1, x12-c2/y1)

B. (-x1, x12-c2/y1)

C. (x1, -x12-c2/y1)

D. (-x1, -x12-c2/y1)

The locus of the foot of the perpendicular drawn from the origin to any chord of the circle x^{2}+y^{2}+2gx+2fy+c=0 which substends a right angle at the origin is

The equation of the circle belonging to the coaxal system of which (2, -3)(0, -4) are the limiting points and passing through the point (2, -1) is

The equation of the circle passing through the points (1, 1), (2, -1), (3, 2) is

If a, b, c are the lengths of tangents from (0, 0) to the circle x^{2}+y^{2}-3x-4y+1=0, x^{2}+y^{2}+4x-6y+4=0, x^{2}+y^{2}-6x-12y+9=0 then the ascending order of a, b, c is

The two circles (x-a)^{2}+(y-b)^{2}=c and (y-b)^{2}+x^{2}=4c have only one real common tangent then