CIRCLE THEOREM: Two tangents drawn from an external point to a circle are equal.
Thus, AB is a tangent to the circle and also BC is another tangent to the circle, both drawn from point B.
AB = BC;
[tex]\begin{gathered} 4x-19=15 \\ 4x=15+19 \\ 4x=34 \\ x=\frac{34}{4} \\ x=8.5 \end{gathered}[/tex]The value of x is 8.5
