$\frac{\sqrt{1296}}{?} = \frac{?}{2.25}$

What will come in the place of the question mark $(?)$ in the following expression?
$\frac{343 \times 49}{216 \times 16 \times 81} = ?$

$7 \frac{1}{2}-\left[2 \frac{1}{4} \div\left\{1 \frac{1}{4}-x\left(1 \frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\right\}\right]=3$. Find the value of $x$.

If $m$ and $n$ are whole numbers such that $m^{n}=121$,then $(m-1)^{n+1}=?$

If $2x + \frac{2}{x} = 1$,then the value of $x^{3} + \frac{1}{x^{3}}$ is

If $\frac{x-a^{2}}{b+c}+\frac{x-b^{2}}{c+a}+\frac{x-c^{2}}{a+b}=4(a+b+c),$ then $x$ is equal to: