Step 1 :
After factoring out $ 3w $ we have:
$$ 27w^{5}-75w = 3w ( 9w^{4}-25 ) $$Step 2 :
Rewrite $ 9w^{4}-25 $ as:
$$ 9w^{4}-25 = (3w^{2})^2 - (5)^2 $$Now we can apply the difference of squares formula.
$$ I^2 - II^2 = (I - II)(I + II) $$After putting $ I = 3w^{2} $ and $ II = 5 $ , we have:
$$ 9w^{4}-25 = (3w^{2})^2 - (5)^2 = ( 3w^{2}-5 ) ( 3w^{2}+5 ) $$