[tex]\Big(-\dfrac{5}{4}\Big)^{-2}:\Big(-\dfrac{5}{4}\Big)^{-6}\cdot \left[\Big(-\dfrac{5}{4}\Big)^2\right]^3 = \\ \\ = \Big(-\dfrac{5}{4}\Big)^{-2}\cdot \Big(-\dfrac{5}{4}\Big)^{6}\cdot \Big(-\dfrac{5}{4}\Big)^{2\cdot 3} = \\ \\ = \Big(-\dfrac{5}{4}\Big)^{-2}\cdot \Big(-\dfrac{5}{4}\Big)^{6}\cdot \Big(-\dfrac{5}{4}\Big)^{6} = \\ \\ = \Big(-\dfrac{5}{4}\Big)^{-2+6+6} =\Big(-\dfrac{5}{4}\Big)^{10} = \Big(\dfrac{5}{4}\Big)^{10} \\ \\ \Rightarrow \text{Inversul este: }\Big(\dfrac{4}{5}\Big)^{10}[/tex]