To determine if each value is in the domain of the function or not we have to remember that in a square root the radicand has to be a non negative number. This means that the radicand in this case have to fullfil:
[tex]\begin{gathered} 8x\ge0 \\ x\ge0 \end{gathered}[/tex]
Therefore for a value to be on the domain on the function it has to be greater or equal to zero, this means that:
-1 is not in domain.
0 is in domain
2 is in domain.
