Yes.
No.
No because 3 cubed is 27 which is a rational number
I assume by 2 cubed you mean 2^3. That equals 2 * 2 * 2 which equals 8. 8 is rational, so yes.
-18 is a rational number
18 to the third power means the same as 18 cubed, which equals 5,832.
There are no factors with rational coefficients.
8
Because the cube root of 343 is an integer.
Yes, any number that can be expressed as a fraction is rational. Since 18 out of 2 is the same as 18/2, it is rational.
-27 is one possible answer.
5832.