The locus of the centre of the circle which makes equal intercepts on the lines `x+y=1 and x+y=5` is

The locus of the centre of the circle which cuts off intercepts of length 2a and 2b from X-axis and Y-axis respectively, is

The locus of the centre of the circle passing through the intersection of the circles x^2+y^2= 1 and x^2 + y^2-2x+y=0 is

The locus of the centre of circle which cuts off an intercept of constant length on the x-axis and which through a fixed point on the y-axis, is

The locus of the centre of circle which cuts off an intercept of constant length on the x-axis and which passes through a fixed point on the y-axis, is

The locus of centre of the circle touching x-axis nad the line y=x is

The locus of centre of the circle touching x-axis nad the line y=x is

The locus of the centre of circles which touch the lines 6x-8y+5=0 and 6x-8y+13=0 is 6x-8y+k=0 then k=

The locus of the centre of the circle which cuts the circles x^(2) + y^(2) + 4x - 6y + 9 = 0 " and " x^(2) + y^(2) - 5x + 4y + 2 = 0 orthogonally is