The centre of the circle passing through the points (a, b), (a, -b), (a+b, a-b) is

The point diametrically opposite to the point P(1, 0) on the circle x²+y²+2x+4y-3=0 is

If the lines 3x + 4y - 14 = 0 and 6x + 8y + 7 = 0 are both tangents to a circle, then its radius is

The locus of the point which moves such that the sum of the squares of its distance from (0, a) is 2r², is

The The limiting points of the coaxal system x²+y²+2µy+9=0 are

If (2, 1 )is limiting point of the coaxal system of which x²+y²-6x-4y-3=0 is a member, then the other limiting point is

The locus of the point of intersection of two perpendicular tangents to the circle x²+y²=a², x²+y²=b² is

The equation of the image of the circle x²+y²-6x-4y+12=0 by the line mirror x+y-1=0 is

The inverse point of (1, 2) w.r.t the circle x²+y²=25 is (5, k), then k=

If the points (2, 3), (0, 2), (4, 5) and (0, t) are concyclic, then t=