Question 613599
Multiply.
{{{3a^(3)-2a^(2)+(-(7a^(3))-(9a^(2)))}}}
{{{3a^(3)-2a^(2)+(-7a^(3)-(9a^(2)))}}}
{{{3a^(3)-2a^(2)+(-7a^(3)-9a^(2))}}}
Use the Distributive Property.
{{{(3-7)a^(3)-2a^(2)-9a^(2)}}}
Simplify. 
{{{-4a^(3)-2a^(2)-9a^(2)}}}
Use the Distributive Property again. 
{{{-4a^(3)+(-2-9)a^(2)}}}
Subtract.
{{{-4a^(3)-11a^(2)}}}

<p>:)