Solve this :

$$\begin{gathered} 3. For x = \frac{3}{4} and y = \frac{-9}{8}, insert a rational number between : \\ \left(i\right) {\left(x+y\right)}^{-1} and x^{-1} + y^{-1} \left(ii\right) {\left(x-y\right)}^{-1} and x^{-1} + y^{-1}. \\ 4. Verify that - \\ {\left(x÷y\right)}^{-1} = x^{-1} ÷ y^{-1} by taking x = \frac{-5}{11}, y = \frac{7}{3} \\ 5. Verify that \left|x+y\right|\le \left|x\right|+\left|y\right| by taking x = \frac{2}{3}, y = \frac{-3}{5}. \\ 6. Find the reciprocals of : \\ \left(i\right) \frac{2}{-5}\times \frac{3}{-7} \left(ii\right) \frac{-4}{3}\times \frac{-5}{-8} \end{gathered}$$