Answer:
Option 2 - 20 unit
Explanation:
Given : If ED = 10 and DB = 3x -8
To find : What is the length of EB ?
Solution :
According to the figure,
ED is equal to DB with similar sign.
So, ED=DB
Substitute the values,
![10=3x-8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/i8i3y84dd5wk33y4g3qkxq9899f1yxvphs.png)
![3x=18](https://img.qammunity.org/2020/formulas/mathematics/high-school/oy8fg47etdwz00anmsua4wkj2nu8643x0j.png)
![x=(18)/(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/aaepsnk98h7ncewktznhqze8r91r2r7mvf.png)
Put back,
![DB = 3x -8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5oka83olf30pnk5wptmb4ckwsqu1ntyu69.png)
unit
Now, length of EB=ED+DB
![EB=10+10](https://img.qammunity.org/2020/formulas/mathematics/middle-school/n4rjlokft0x9o6wv2zgjj88ktct8wrsw0y.png)
unit
Therefore, option 2 is correct.