For what value of `k` is the circle `x^2 + y^2 + 5x + 3y + 7 = 0` and `x^2 + y^2 - 8x + 6y + k = 0` cut each other orthogonally.

Show that the circles x^2 + y^2 - 2x-6y-12=0 and x^2 + y^2 + 6x+4y-6=0 cut each other orthogonally.

If the two circle x^(2) + y^(2) - 10 x - 14y + k = 0 and x^(2) + y^(2) - 4x - 6y + 4 = 0 are orthogonal , find k.

Two circles x^(2) + y^(2) -2kx = 0 and x^(2) + y^(2) - 4x + 8y + 16 = 0 touch each other externally.Then k is

The locus of the centers of the circles which cut the circles x^(2) + y^(2) + 4x – 6y + 9 = 0 and x^(2) + y^(2) – 5x + 4y – 2 = 0 orthogonally is

Find the equation of circle passing through the origin and cutting the circles x^(2) + y^(2) -4x + 6y + 10 =0 and x^(2) + y^(2) + 12y + 6 =0 orthogonally.

If the curve ax^(2) + 3y^(2) = 1 and 2x^2 + 6y^2 = 1 cut each other orthogonally then the value of 2a :

For what values of k is the system of equations 2k^2x + 3y - 1 = 0, 7x-2y+ 3 - 0, 6kx + y+1=0 consistent?

For what value of k is the line x-y+2+k(2x+3y)=0 parallel to the line 3x+y=0 ?