Question

How do I solve for X?

Answer 1

The distance from the external point ^2 = The external segment of the secant * the full length of the secant.
tangent distance = 6
External portion of the secant = 3
Full length of the secant = x + 3

6^2 = 3*(x + 3) Remove the brackets. 
36 = 3x + 9  Subtract 9 from both sides.
36 - 9 = 3x
27 = 3x Divide by 3
x = 9  <<<<<<<Answer.