Simplify the following:

$\frac{3}{\sqrt{8}}+\frac{1}{\sqrt{2}}$

Find the value

$625^{\frac{3}{4}}$

Fill in the blanks so as to make each of the following statements true (Final answer only)

$(64)^{-\frac{1}{6}}=\ldots \ldots$

For each question, select the proper option from four options given, to make the statement true : (Final answer only)

$\left(5^{-2}\right)^{3}=\ldots \ldots \ldots$

Rationalise the denominator in each of the following and hence evaluate by taking $\sqrt{2}=1.414, \sqrt{3}=1.732$ and $\sqrt{5}=2.236,$ upto three places of decimal.

$\frac{4}{\sqrt{3}}$

Simplify : $(3 \sqrt{5}-5 \sqrt{2})(4 \sqrt{5}+3 \sqrt{2})$