The length of the common chord of the circles ` x^(2) + y^(2) + 2hx = 0 , x^(2) + y^(2) - 2ky = 0 ` is

The length of the common chord of the circles x^(2) + y^(2) + 2hx + a^(2) = 0 , x^(2) + y^(2) - 2ky - a^(2) = 0 is

The length of the common chord of the circles x^(2) + y^(2) + 2gx + c = 0 and x^(2) + y^(2) + 2fy - c = 0 is

The length of the common chord of the circles x^(2) + y^(2) + 2x + 3y + 1= 0 , x^(2) + y^(2) + 4x + 3y + 2 =0 is

The length of the common chord of the two circles x^(2) + y^(2) - 4y = 0 " and " x^(2) + y^(2) - 8x - 4y - 11= 0 is

The length of the common chord of the circles x^(2)+y^(2)-2x-1=0 and x^(2)+y^(2)+4y-1=0 , is

The length of the common chord of the circles x^(2)+y^(2)-2x-1=0 and x^(2)+y^(2)+4y-1=0 , is