1. Any Quantity to the 0 power simplifies down to 1
2. Any Quantity to the - power gets reciprocated.
ex)
3. To multiply two quantities raised to powers you add the powers
so using these rules and taking things one step at a time
--> Simplifying the quantity to the 0 power
= --> Simplify the negative external powers
= --> Squaring r^-3s^2
= --> Multiply through by -2r
= --> dividing by s^2
= --> Writing with positive exponents
=