The number is 142
you first make an equation ;
86+x=2x-56
Add 56 to both sides
142+x=2x
Subtract x from both sides
142=x
Answer:

Step-by-step explanation:
You only need to isolate the term a to solve this problem.
Add by 3 from both sides.

Solve.
0+3=3
a/7<3
Multiply by 7 from both sides.

Solve.
3*7=21
<u>a<21</u>
As a result, the solution is a<21, which is our answer.
So, when finding the volume, we would just add up every side, and from the question above, it look like that the numbers that we would be adding are the following above.

The volume would be 11.2
Good question sir but idk