= [8a3 + 12a2b + 6ab2 + b3] – [8a3 – 12a2b + 6ab2 – b3]

The given expression is:

[8a³ + 12a²b + 6ab² + b³] - [8a³ - 12a²b + 6ab² - b³]

To simplify this, we subtract the terms in the second square brackets from the terms in the first square brackets.

This gives us:

8a³ - 8a³ + 12a²b - (-12a²b) + 6ab² - 6ab² + b³ - (-b³)

Simplifying further, we get:

0a³ + 24a²b + 0ab² + 2b³

So, the simplified form of the given expression is:

24a²b + 2b³