Answer:
x = 10
Explanation:
What I did is I set up a proportion based on the bigger triangle (ACED) and the smaller triangle (ABC). I did :
10+x/x = 16/8
8(10+x) = 16x
80 + 8x = 16x (distribute)
80 = 8x (subtract 8x from both sides)
x = 10 (divide 8 on both sides)
:)