The equation of the common tangent at the point contact of the circles x²+y²-10x+2y+10=0, x²+y²-4x-6y+12=0 is

The number of tangents that can be drawn from (6, 0) to the circle x²+y²-4x-6y-12=0 are

The locus of the middle points of portions of the tangents to the circle x²+y²=a² terminated by the axes is

If the length of the tangets from two points A, B to a circles are 6, 7 respectively. If A, B are conjugate points then AB=

The length of the tangent from a point on the circle x²+y²+2gx+2fy+c=0 to the circle x²+y²+2gx+2fy+c^’=0 is

The normal of the circle(x-2)²+(y-1)²=16 which bisects the chord cut off by the line x-2y-3=0 is

The length of the common chord of the circles (x-a)²+(y-b)²=c² and (x-b)²+(y-a)²=c²

The external centre of similitude of the two circles x²+y²-2x-6y+9=0, x²+y²=4 is

The longest distance from (-3, 2) to the circles x²+y²-2x+2y+1=0 is

If the equation of the circle passing through the origin and the points of intersection of the two circles x²+y²-4x-6y-3=0, x²+y²+4x-2y-4=0 is x²+y²+2ax+2by+c=0  then the ascending order of a, b,c is