Explicație pas cu pas:
[tex]{\left( - 1 + \frac{2}{3}\right)}^{ - 3} \div \frac{a}{b} = {\left( - \frac{1}{3} \right)}^{ - 1} \\ [/tex]
[tex]{\left( - \frac{1}{3}\right)}^{ - 3} \cdot \frac{b}{a} = - 3 \\ [/tex]
[tex]{( - 3)}^{3} \cdot \frac{b}{a} = - 3 \\ [/tex]
[tex]\frac{b}{a} = \frac{3}{ {3}^{3} } \implies \red{\bf \frac{b}{a} = \frac{1}{9}} \\ [/tex]
