Answer:
x = 6 units
Step-by-step explanation:
BD and CD are tangents to the circle from point D.
Since, tangents drawn from external point to a circle are congruent.
[tex] \therefore \: BD \cong CD \\ \therefore \: 4x - 9 = 15 \\ \therefore \: 4x = 15 + 9 \\ \therefore \: 4x = 24 \\ \therefore \: x = \frac{24}{4} \\ \huge \red{ \boxed{\therefore \: x = 6 \: units}}[/tex]
