If radius of circle ` 2x^(2) + 2y^(2) - 8x + 4fy + 26 = 0 `
is 4, then f=

Circle x^(2) + y^(2) - 8x + 4y + 4 = 0 touches

The radius of the circle x^(2) + y^(2) - 2x + 4y - 4 = 0 is ______

The circle x^(2) + y^(2)- 8x + 4y + 4=0 touches

The circle x^2 + y^2 - 8x + 4y + 4 = 0 toches

The circle x^2 + y^2 - 8x + 4y +4 = 0 touches

State which of the following is the radius of the circle x^(2) + y^(2) + 4x - 8y - 5 = 0 ?

If the circle x^(2) + y^(2) + 2x - 2y + 4 = 0 cuts the circle x^(2) + y^(2) + 4x - 2fy + 2 = 0 orthogonally , then f =