The problem asks to simplify the expression $(8a^3 - 2a^2 - 9a + 8) + (8a + 6) - (-a^2 - a + 2)$. This involves adding and subtracting polynomials.

1. Problem Description

The problem asks to simplify the expression $(8a^3 - 2a^2 - 9a + 8) + (8a + 6) - (-a^2 - a + 2)$. This involves adding and subtracting polynomials.

2. Solution Steps

First, we remove the parentheses, remembering to distribute the negative sign in the last term.

$8a^3 - 2a^2 - 9a + 8 + 8a + 6 + a^2 + a - 2$

Next, we combine like terms.

The $a^3$ term is $8a^3$.

The $a^2$ terms are $-2a^2 + a^2 = -a^2$.

The $a$ terms are $-9a + 8a + a = -9a + 9a = 0a = 0$.

The constant terms are $8 + 6 - 2 = 14 - 2 = 12$.

Therefore, the simplified expression is $8a^3 - a^2 + 12$.

3. Final Answer

$8a^3 - a^2 + 12$