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 :

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

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

The lenth of the portion of the common tangent to x^(2)+y^(2)=16 and 9x^(2)+25y^(2)=225 between the two points of contact is

The lenth of the portion of the common tangent to x^(2)+y^(2)=16 and 9x^(2)+25y^(2)=225 between the two points of contact is

If e_(1) and e_(2) be the eccentricities of the hyperbolas 9x^(2) - 16y^(2) = 576 and 9x^(2) - 16y^(2) = 144 respectively, then -