Answer:
[tex]x=3\sqrt{7}[/tex]
Step-by-step explanation:
If a tangent and a secant connect to an exterior point of a circle, the tangent squared is equal to the product of the two segments the secant creates.
Therefore, we have:
[tex]x^2=7 \cdot 9,\\x^2=63,\\x=\sqrt{63}=\boxed{3\sqrt{7}}[/tex]
