Answer
$\color{blue}{(2m-3n)(4m^2+6mn+9n^2)}$
Work Step by Step
With $8m^3=(2m)^3$ and $27n^3=(3n)^3$, the given polynomial is equivalent to:
$=(2m)^3-(3n)^3$
Factor using the formula $a^3-b^3=(a-b)(a^2+ab+b^2)$ with $a=2m$ and $b=3n$ to obtain:
$=(2m-3n)[(2m)^2+(2m)(3n) + (3n)^2]
\\=\color{blue}{(2m-3n)(4m^2+6mn+9n^2)}$
