Evaluate $\frac{(2.39)^{2}-(1.61)^{2}}{2.39-1.61}$

The value of $\frac{9^{2} \times 18^{4}}{3^{16}}$ is

Which of the following is $TRUE$?
$I.$ $\sqrt[3]{11} > \sqrt{7} > \sqrt[4]{45}$
$II.$ $\sqrt{7} > \sqrt[3]{11} > \sqrt[4]{45}$
$III.$ $\sqrt{7} > \sqrt[4]{45} > \sqrt[3]{11}$
$IV.$ $\sqrt[4]{45} > \sqrt{7} > \sqrt[3]{11}$

$3 . \overline{87} - 2 . \overline{59} = ?$

If $a * b = 2a - 3b + ab$,then $3 * 5 + 5 * 3$ is

The value of $\frac{1}{a^{2}+a x+x^{2}}-\frac{1}{a^{2}-a x+x^{2}}+\frac{2 a x}{a^{4}+a^{2} x^{2}+x^{4}}$ is