[tex] \frac{a^4.b^{-3}}{ab^{-2}}= \\ \\ \frac{a^4.\frac{1}{b^3}}{a.\frac{1}{b^2}}= \\ \\ \frac{\frac{a^4}{b^3}}{\frac{a}{b^2}}= \\ \\ \frac{a^4}{b^3}.\frac{b^2}{a}= \\ \\ \frac{a^4}{a}.\frac{b^2}{b^3}= \\ \\ \frac{a^3.a}{a}.\frac{b^2}{b.b^2}= \\ \\ \frac{a^3}{1}.\frac{1}{b}= \frac{a^3}{b}[/tex]
