According to the tangent-secant theorem, we know that:
[tex]x^2=9\times(7+9)[/tex]
Solve for x^2:
[tex]\begin{gathered} \Rightarrow x^2=9\times16 \\ \Rightarrow x^2=144 \\ \Rightarrow x=\sqrt[]{144} \\ \Rightarrow x=12 \end{gathered}[/tex]
Therefore, the value of x is:
[tex]12[/tex]
