## Elementary Algebra

$\frac{4xy}{9z}$
We use the rule $\frac{a^{m}}{a^{n}}=a^{m-n}$ to help us cancel out common factors in the numerator and denominator: $\frac{32xy^{2}z^{3}}{72yz^{4}}$ =$\frac{32}{72}\times x\times\frac{y^{2}}{y}\times\frac{z^{3}}{z^{4}}$ =$\frac{4}{9}\times x\times y^{2-1}\times z^{3-4}$ =$\frac{4}{9}\times x\times y^{1}\times z^{-1}$ =$\frac{4}{9}\times x\times y^{1}\times \frac{1}{z^{1}}$ =$\frac{4xy}{9z}$