A. x2+y2+2x-2y+1=0

B. 2x2+2y2+12x-2y+1=0

C. x2+y2+2x+12y-11=0

D. 3x2+3y2+20x-21y+1=0

The orthocentre of triangle formed by the lines x + 3y = 10 and 6x<sup>2</sup> + xy - y<sup>2</sup> = 0 is:

B and C are two points on the circle x^{2}+y^{2}=a^{2}. From a point A(b, c) on that circle AB=AC=d. The equation to Bc is

The locus of the centre of the circles which touché both the circles x^{2}+y^{2}=a^{2} and x^{2}+y^{2}=4ax externally has the equation

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

The length of the intercept made by the circle x^{2}+y^{2}+10x-12y-13=0 on y-axis is