Answer:
[tex]x=23[/tex]
Step-by-step explanation:
In a circle, given a tangent line and a secant, the length of the tangent line squared is equal to the product of the two lines formed by the secant.
Therefore, we have the following equation:
[tex]8^2=4(x-7),\\64=4(x-7),\\16=x-7.\\x=\boxed{23}[/tex]
