Answer:
C. b^27
Step-by-step explanation:
By the definition of exponents
[tex](b^9)^3=b^9*b^9*b^9[/tex]
And since for any real numbers [tex]r,x,[/tex] and [tex]y[/tex]
[tex]r^x*r^y=r^{(x+y)}[/tex]
This makes
[tex](b^9)^3=b^9*b^9*b^9=b^{{9+9+9}}=\boxed{b^{27}}[/tex]
Which is choice C.
Alternatively, we could use the identity
[tex](r^x)^y=r^{xy}[/tex]
in which case
[tex](b^9)^3=b^{(9*3)}= \boxed{b^{27}}[/tex]
which is the same answer.