#### Answer

$(b^{x})^{y}=b^{xy}$
This is known as third Law of Exponents; where x and y are real numbers.

#### Work Step by Step

We already know that $lnb^{r}=rlnb$
Now,
$(b^{x})^{y}=e^{yln(b^{x})}$
Also, $b^{x}=e^{xlnb}$
This implies
$e^{yxlnb}=e^{xylnb}$
Hence, $(b^{x})^{y}=b^{xy}$
This is known as third Law of Exponents; where x and y are real numbers.