Answer
$\color{blue}{(5x-3)(25x^2+15x+9)}$
Work Step by Step
With $125x^3=(5x)^3$ and $27=3^3$, the given polynomial is equivalent to:
$=(5x)^3-3^3$
Factor using the formula $a^3-b^3=(a-b)(a^2+ab+b^2)$ with $a=5x$ and $b=3$ to obtain:
$=(5x-3)[(5x)^2+(5x)(3) + 3^2)
\\=\color{blue}{(5x-3)(25x^2+15x+9)}$
