Answer
$(5m^2-6)(25m^4+30m^2+36)$
Work Step by Step
Using $a^3\pm b^3=(a\pm b)(a^2\mp ab+b^2)$ or the factoring of two cubes, the factored form of the given expression, $
125m^6-216
,$ is
\begin{array}{l}\require{cancel}
(5m^2-6)[(5m^2)^2+5m^2(6)+(6)^2]
\\\\=
(5m^2-6)(25m^4+30m^2+36)
.\end{array}
