If a variable circle cuts two circles `x^2+ y^2= 1` and `x^2 +y^2 -2x-2y-7=0` orthogonally than loucs of centre of variable circle is

If two circles (x+4)^(2)+y^(2)=1 and (x-4)^(2)+y^(2)=9 are touched extermally by a circle, then locus of centre of variable circle is

If two circles (x+4)^(2)+y^(2)=1 and (x-4)^(2)+y^(2)=9 are touched extermally by a circle, then locus of centre of variable circle is

If two circles (x+4)^(2)+y^(2)=1 and (x-4)^(2)+y^(2)=9 are touched extermally by a circle, then locus of centre of variable circle is

The circle S=0 cuts the circle x^(2)+y^(2) -4x+2y-7=0 orthogonally if (2,3) is the centre of the circle S=0 then its radius is

A variable circle cuts each of the circles x^(2)+y^(2)-2x=0&x^(2)+y^(2)-4y-5=0 orthogonally.The variablecircle passes through two fixed points whose co-ordinates are

The locus of the centre of a circle which cuts the circles 2x^(2)+2y^(2)-x-7=0 and 4x^(2)+4y^(2)-3x-y=0 orthogonally is a straight line whose slope is (A)-1 (B) 1(C)-2(D)-(5)/(2)

If the circle x^(2)+y^(2)+2 x-2 y+4=0 cuts the circle x^(2)+y^(2)+4 x+2 f y+2 =0 orthogonally then f=

If the circle x^2 + y^2 + 2x - 2y + 4 = 0 cuts the circle x^2 + y^2 + 4x - 2fy +2 = 0 orthogonally, then f =