To simplify \((13)^6 \cdot (13)^3\) using the Product Rule of Exponents, you add the exponents when multiplying like bases:
\[ (13)^6 \cdot (13)^3 = (13)^{6+3} = (13)^9 \]
Thus, the equivalent form of \((13)^6 \cdot (13)^3\) is:
\((13)^9\)
So, the correct response is:
(13)9