Question 199305
You  do  not  define  x,  but  we  presume  it  is  the  distance  between  centers  of  the  circles.
.
a  rough  sketch  helps
.
remember  that  tan  to  circles  make  perpendicular  angles  to  radius at  intersection
.
if  we  use  the  base  as  line  ZY,  we  see that  it  is  almost  a rectangle,  
.
if  we  take  the  rectangle  out,  we  are  left  with  a  right  triangle,  sides 25 ,  and  (12-9=3),
.
with  hypotenuse "x",,,,,,we  use  pythagorous  to  solve
.
x^2 = 3^3 + 25^2,,,,, x= 25.18