Question 260738
{{{(12a^3 - 9a^2 + 8) + (6a^3 + 4a^2 -a)}}} Start with the given expression



{{{12a^3 - 9a^2 + 8 + 6a^3 + 4a^2 -a}}} Remove the parenthesis



{{{(12a^3+ 6a^3)+( - 9a^2+ 4a^2)-a + 8}}} Group like terms.



{{{18a^3-5a^2-a + 8}}} Combine like terms.



So {{{(12a^3 - 9a^2 + 8) + (6a^3 + 4a^2 -a)=18a^3-5a^2-a + 8}}}