If the circles `x^2+y^2+2ax+c=0` and `x^2+y^2+2by+c=0` touch each other , prove that c is always positive .

If the circles x^(2)+y^(2)+2ax+b=0 and x^(2)+y^(2)+2cx+b=0 touch each other (a!=c)

If two circles x^(2) + y^(2) - 2ax + c = =0 and x^(2) + y^(2) - 2by + c = 0 touch each other , then c =

The two circles x^(2)+y^(2)-cx=0 and x^(2)+y^(2)=4 touch each other if:

The circles x^(2)+y^(2)+2x-2y+1=0 and x^(2)+y^(2)-2x-2y+1=0 touch each other

If the circles x^(2)+y^(2)+2ax+c=0 and x^(2)+y^(2)+2by+c=0 touch each other,then find the relation between a,b and c.

If the circles x^(2)+y^(2)=9 and x^(2)+y^(2)+8y+C=0 touch each other,then c is equal to

If the circles x^(2)+y^(2)+2gx+2fy=0and x^(2)+y^(2)+2g'x+2f'=0 touch each other then prove that f' f = fg .

If two circles x^2 + y^2 + ax + by = 0 and x^2 + y^2 + kx + ly = 0 touch each other, then (A) al = bk (B) ak = bl (C) ab = kl (D) none of these