A. p=q

B. pOA=qOB

C. pOB=qOA

D. p2=q2

The circle x^{2}+y^{2}=4 cuts the circle x^{2}+y^{2}-2x-4=0 at the points A and B. If the circle x^{2}+y^{2}-4x-k=0 passes through A and B then the value of k is

The equation of the circle passing through (-7, 1) and having centre at (-4, -3) is

The system of circles orthogonal to x^{2}+y^{2}+2x+4y+7=0 is a member, then the equation of the orthogonal system is

The circle described on the line joining the points (0, 1), (a, b) as diameter cuts the x-axis in points whose abscissa are roots of the equation

If the length of the tangent from (h, k) to the circle x^{2}+y^{2}=16 is twice the length of the tangent from the same point to the circle x^{2}+y^{2}+2x+2y=0, then