Middle School

Which are sums of perfect cubes? Check all that apply.

- [tex]8x^6 + 27[/tex]
- [tex]x^9 + 1[/tex]
- [tex]81x^3 + 16x^6[/tex]
- [tex]x^6 + x^3[/tex]
- [tex]27x^9 + x^{12}[/tex]
- [tex]9x^3 + 27x^9[/tex]