Simplify 6a^3+2a^2-8a-9-8a^3-a^2-6a+1

$6 a^{3} + 2 a^{2} - 8 a - 9 - 8 a^{3} - a^{2} - 6 a + 1$

Subtract $8 a^{3}$ from $6 a^{3}$ .

$- 2 a^{3} + 2 a^{2} - 8 a - 9 - a^{2} - 6 a + 1$

Subtract $a^{2}$ from $2 a^{2}$ .

$- 2 a^{3} + a^{2} - 8 a - 9 - 6 a + 1$

Subtract $6 a$ from $- 8 a$ .

$- 2 a^{3} + a^{2} - 14 a - 9 + 1$

Add $- 9$ and $1$ .

$- 2 a^{3} + a^{2} - 14 a - 8$