Find : $\sqrt{7+2 \sqrt{10}}$

If two positive integers $a$ and $b$ are written as $a = x^3 y^2$ and $b = x y^3$,where $x$ and $y$ are prime numbers,then $HCF(a, b)$ is:

Every odd integer $a$ is in the form of $\ldots \ldots \ldots \ldots$ where,$k \in Z$.

The product of the greatest common divisor ($G$.$C$.$D$.) and the least common multiple ($L$.$C$.$M$.) of two positive integers $a$ and $b$ is equal to: (where $a, b \in N$)

Simplify: $\frac{2}{\sqrt{5}-\sqrt{3}} + \frac{4}{\sqrt{10+\sqrt{84}}} - \frac{2}{\sqrt{7}-\sqrt{5}}$

State whether the following rational number has a terminating decimal expansion or not. If it has,then find it: $\frac{9}{30}$