`" Equation of common tangent of "9x^(2)+16y^(2)=144,y^(2)-x+4=0" and "x^(2)+y^(2)-12x+32=0" is "`

If x=k is the equqtion of a common tangent to the curves 9x^(2)+16y^(2)=144 ,y^(2)-x+4=0 and x^(2)+y^(2)-12x+32=0 then k is equal to _____

A common tangent to 9x^(2) - 16y^(2) = 144 and x^(2) + y^(2) = 9 is

A common tangent to 9x^(2)-16y^(2)=144 and x^(2)+y^(2)=9, is

Equation of a common tangent to x^(2)+y^(2)=16" and "9x^(2)+25y^(2)=225 is :

A common tangent to 9x^(2)+164;y^(2)-x+4=08x^(2)+y^(2)-12x+32=0

The number of common tangents of the circles x^(2) +y^(2) =16 and x^(2) +y^(2) -2y = 0 is :