Question

Which law would you use to simplify the expression p/q^3?
power of a power
power of a quotient
quotient of powers
power of a product

Answer 1

None of those four is the direct law you need. The appropriate rule is the negative-exponent rule:
a^{-n} = 1/a^n.

So p/q^3 = p · q^{-3}.

(If p and q had the same base, then you could use the quotient-of-powers law a^m/a^n = a^{m-n}.)