Answer:
6.7
Explanation:
Use the Triangle Angle Bisector Theorem:
If an angle of a triangle is bisected, then the bisector splits the opposite sides into two segments. The length of each segment is proportional to its adjacent side.
In other words,
AB/AD = BC/CD
x/5 = 8/6
6x = 5 × 8
6x = 40
x = 20/3
x = 6.6666...
Answer: 6.7