The system of circle ` x^(2) + y^(2) - 2 muy = 0 ` is

The system of circles is x^(2) + y^(2) + 2 lambdax - 5 = 0 is

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

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

The equation to the line joining the centres of the circles belonging to the coaxial system of circles 4x^(2) + 4y^(2) - 12x + 6y - 3 + lambda (x + 2y - 6) = 0 is

The differential equation of co-axial system of circles x^(2) + y^(2) -4 + lamda (2x + y - 5) = 0 is

If (1,-2) is a limiting point of a coaxal system of which the circle x^(2) + y^(2) - x - 2y - 1 = 0 is a member , then the equation of a circle of the system passing through origin is

The number of real circles culting orthogonally the circle x^(2) + y^(2) + 2x -2y + 7 = 0 is