ANSWER :
A. 15
EXPLANATION :
Recall the secant-secant formula :
[tex](\text{ whole secant})\times(\text{ external part})=(\text{whole secant})\times(\text{external part})[/tex]
That will be :
[tex](8+19)\times8=(x+9)\times9[/tex]
Solving for x :
[tex]\begin{gathered} 27\times8=9x+81 \\ 216=9x+81 \\ 216-81=9x \\ 135=9x \\ 9x=135 \\ x=\frac{135}{9}=15 \end{gathered}[/tex]
