Answer:
B.
Step-by-step explanation:
AD, the entire segment, is composed of the three segments AB, BC, and CD. In other words:
[tex]AD=AB+BC+CD[/tex]
Since AB=CD, we can substitute:
[tex]AD=CD+BC+CD\\ AD=2CD+BC[/tex]
We know that CD is 9 and BC is 5x. AD is 53. So, substitute:
[tex]53=2(9)+5x[/tex]
Solve for x:
[tex]\begin{aligned} 53&=18+5x \\ 35&=5x \\ 7&=x \end{aligned}[/tex]
The value of x is 7.
Hence, our answer is B.
