+126 A Unit circle has center at (5,0) and second circle with a radius 2 units has its center at (11,0). A common tangent to both circles intersects x-axis at Q(a,0) what is value of a
+126 Hi,
Could you please explain how you arrived at the answer? I would like to understand how to solve these problems.
Thanks
+1641 I think both of you are correct. (At least regarding the word common 
)
In Alan's case, the tangent is called a Common external tangent. (or common direct tangent)
In your case, it's called a Common internal tangent. (or common indirect tangent)
But if circles are tangent to each other, then there are 2 external and 1 internal tangent.
Which one of these two is more common? 
Btw, the first answer is mine.
