$\sqrt{80} + 3\sqrt{245} - \sqrt{125} = ?$

In the following questions,two equations numbered $I$ and $II$ are given. You have to solve both the equations and give the answer.
$I$: $\sqrt{25 x^{2}} - 125 = 0$
$II$: $\sqrt{361} y + 95 = 0$

The smallest number to be added to $680621$ to make the sum a perfect square is

If $3 \sqrt{5}+\sqrt{125}=17.88$,then what will be the value of $\sqrt{80}+6 \sqrt{5}$?

If $a^{2}=2,$ then $(a+1)$ is equal to

If $\frac{\sqrt{256}}{\sqrt{x}}=2,$ then $x$ is equal to