Only 4th one
Q.1. Find the square of
(iv) $\frac{3a}{2b}-\frac{2b}{3a}$

Dear Student,
Please find below the solution to the asked query:

$$\begin{gathered} \mathrm{Square} \mathrm{of} \left(\frac{3\mathrm{a}}{2\mathrm{b}}-\frac{2\mathrm{b}}{3\mathrm{a}}\right) \\ ={\left(\frac{3\mathrm{a}}{2\mathrm{b}}-\frac{2\mathrm{b}}{3\mathrm{a}}\right)}^2 \\ ={\left(\frac{3\mathrm{a}}{2\mathrm{b}}\right)}^2+{\left(\frac{2\mathrm{b}}{3\mathrm{a}}\right)}^2-2\times \frac{3\mathrm{a}}{2\mathrm{b}}\times \frac{2\mathrm{b}}{3\mathrm{a}} \left[\mathrm{As} {\left(\mathrm{a}-\mathrm{b}\right)}^2={\mathrm{a}}^2+{\mathrm{b}}^2-2\mathrm{ab}\right] \\ =\frac{9{\mathrm{a}}^2}{4{\mathrm{b}}^2}+\frac{4{\mathrm{b}}^2}{9{\mathrm{a}}^2}-2 \end{gathered}$$

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