The answer is 5x because when you do the math 12 subtracted by 7 equals 5 then you add the x at the end.
It is given in the question that

And 
can also be written as

Therefore,


That gives,

Answer:
The second choice
Step-by-step explanation:
It is .15 because 1/8 in decimal forma is .125
Since ED and DB are exactly half of EB, we can set ED and DB equal to each other.
x + 4 = 3x - 8
Subtract x from both sides. Add 8 to both sides
12 = 2x
Divide both sides by 2
6 = x
ED = 6 + 4 = 10
ED = DB = 10
EB = ED +DB = 10 + 10 = 20
ED = 10
DB = 10
EB = 20