Given the expression :
[tex]216x^3-1[/tex]We need to factor the given expression, it it a difference of cubic :
So, we should know that :
[tex]x^3-a^3=(x-a)\cdot(x^2+ax+a^2)[/tex]For the given expression :
[tex]\begin{gathered} 216x^3=6x\cdot6x\cdot6x \\ \end{gathered}[/tex]So, the factors will be :
[tex](216x^3-1)=(6x-1)(36x^2+6x+1)[/tex]