Next, let's talk about the laws of exponents. These laws help combine terms with the same base. In this problem, we deal with two different bases: \(r\) and \(s\). According to the law of exponents, \(a^m \cdot a^n = a^{m+n}\). This means that we can add the exponents when multiplying like bases.
- For \(r\)-terms: \( r^{-3} \cdot r^{4} = r^{-3+4} = r^{1} \).
So, \(r^{-3} \cdot r^{4} = r \).
- For \(s\)-terms: \( s^{9} \cdot s^{-5} = s^{9-5} = s^{4} \).
So, \(s^{9} \cdot s^{-5} = s^{4} \).
The laws of exponents help simplify expressions involving powers efficiently.