Question

Please help.
Is algebra.
PLEASE HELP NO LINKS OR FILES.
I don't want links.

Answer 1

`3d^3`

Explanation:

The contents of the box must make

`7d^3 - \text{ BOX } = 4d^3`

To get
`7d^3` down to
`4d^3`, you have to subtract
`3d^3`