Let circles $C_1$    and $C_2$   on Argand plane be given by  $\left|z+1\right|=3$ and  $\left|z-2\right|=7$  respectively. If a variable circle C be such that   

it touches $C_1$   externally and $C_2$   internally .The  locus of  center of  variable circle describes a conic E. If eccentricity of E can be written in simplest from and p/q when p, q  

 then find the value of |q – p|