Find the equation of the circle drawn on the line joining the centres of the circles as diameter: `(i) x^2+y^2-6x+8y-20=0andx^2+y^2+8x-6y=0`

Find the equation of the circle passing through the points of intersection of the circles x^(2)+y^(2)-8x-6y-21=0 x^(2)+y^(2)-2x-15=0and(1,2)

Find the equation of the circle passing through the centre of the circle x^(2)+y^(2)+8x+10y-7=0 and concentric with the circle x^(2)+y^(2)-4x-6y=0

Find the equation of the circle passing through the centre of the circle x^2 +y^2 -4x-6y=8 and being concentric with the circle x^2 +y^2 - 2x-8y=5 .

Find the distance between the centres of the circles x^(2)-y^(2)+8x+10y-2=0andx^(2)-y^(2)+2x+2y-1=0 .

Find the distance between the centres of the circles x^(2)+y^(2)+8x+10y-2=0andx^(2)+y^(2)+2x+2y-1=0 .

Find the length of the tangent, drawn to the circles x^2+y^2+10x-6y+8=0 from the centre of the circle x^2+y^2-4x=0