If the circles `x^(2) +y^(2) - 6x – 8y +c = 0 and x^(2) + y^(2) =9` have three common tangent then c=

If the circleS x^(2)+y^(2)-6 x-8 y+c=0 and x^(2)+y^(2)=9 have three common tangtnts then c=

The circles x^(2) +y^(2) + 2ax +c =0 and x^(2) +y^(2) +2bx +c =0 have no common tangent if

The common tangents to the circles x^(2) +y^(2) +2x = 0 and x^(2) +y^(2) -6x= 0 from a triangle which is :

the no.of possible integral values of m for which the circle x^(2)+y^(2)=4 and x^(2)+y^(2)-6x-8y+m^(2)=0 has exactly two common tangents are

If the circles x^(2) +y^(2) = a and x^(2) + y^(2) - 6x - 8y + 9 = 0 touch externally then a =