how do you factor this 8x^3+27

That is (2x)^3 + 3^3
in general
a^3 + b^3 = a^3 + 3a^2b + 3ab^2 + b^3
so
(2x)^3 + 3(2x)^2(3) + 3 (2x)(3)^2 + 27
which is
8x^3 + 36x^2 + 18x + 27

I was thinking of binomial expansion. This is not.
a^3+b^3 = (a+b)(a^2-ab+b^2)

so
(2x+3)(4x^2-6x+9)

thanks!