Question 35395
Well {{{(3x + 3y)^2(2x + 3y)}}}
{{{(3x + 3y)^2=(3x+3y)(3x+3y)=9x^2+6xy+9y^2}}}
{{{(9x^2+6xy+9y^2)(2x+3y)=18x^3+12x^2y+18xy^2+27x^2y+18xy^2+27y^3=18x^3+39x^2y+36xy^2+27y^3}}}  The last equation is your answer.

Hope this helps,
lyra