What will come in the place of the question mark $(?)$ in the following equation?
$3463 \times 295 - 18611 = ? + 5883$

If $m^{n} = 169$,what is the value of $(m+1)(n-1)$?

If $\sqrt{x} - \sqrt{y} = 1$ and $\sqrt{x} + \sqrt{y} = 17$,then $\sqrt{xy} = ?$

$4^{11} + 4^{12} + 4^{13} + 4^{14}$ is divisible by:

$\left(\frac{10.3 \times 10.3 \times 10.3 + 1}{10.3 \times 10.3 - 10.3 + 1}\right)$ is equal to (in $.3$)

$A$ boy was asked to multiply a given number by $\frac{8}{17}$. Instead,he divided it by $\frac{8}{17}$ and got the result $225$ more than what he should have got if he had multiplied the number by $\frac{8}{17}$. The given number was: