Find k if the following pairs of circles are orthogonal.
` x^2 + y^2 + 2by - k = 0, x^2 + y^2 + 2ax + 8 = 0 `.

Find k if the following pairs of circles are orthogonal. x^2 + y^2 + 4x + 8 = 0, x^2 + y^2 - 16y + k = 0

Find k if the following pairs of circles are orthogonal. x^2 + y^2 - 5x - 14y - 34 = 0. x^2 + y^2 + 2x + 4y + k = 0

Find k if the following pairs of circles are orthogonal. x^2 + y^2 - 6x - 8y + 12 = 0 , x^2 + y^2 - 4x + 6y + k = 0

Find k if the following pairs of circles are orthogonal x^2+y^2-16y-k=0 x^2+y^2+4x-8=0

Find k if the following pairs of circles are orthogonal x^2+y^2-16y-k=0 x^2+y^2+4x-8=0

Find k if the following pairs of circles are orthogonal x^(2)+y^(2)-16y+k-0, x^(2)+y^(2)+4x+8=0

Find k if the following pairs of circles are orthogonal x^2+y^2-6x-8y+12=0 x^2+y^2-4x+6y+k=0

Find k if the following pairs of circles are orthogonal x^2+y^2-6x-8y+12=0 x^2+y^2-4x+6y+k=0

Find k if the following pairs of circles are orthogonal x^2+y^2-6x-8y+12=0 x^2+y^2-4x+6y+k=0

Find k if the following pairs of circles are orthogonal x^(2)+y^(2)-6x-8y+12=0,x^(2)+y^(2)-8x+6y+k=0