21.
If $${\log _{1000}}x = - \frac{1}{4}{\text{,}}$$    then the value of x is = ?

22.
$$\frac{{\log \sqrt 8 }}{{\log 8}}\,\,{\text{is equal to = ?}}$$

23.
The value of $$\frac{{6{\text{ }}{{\log }_{10}}1000}}{{3{\text{ }}{{\log }_{10}}100}}$$   is equal to -

24.
If $${\log _2}\left[ {{{\log }_3}\left( {{{\log }_2}x} \right)} \right] = 1,$$     then x is equal to = ?

25.
What is the value of the following expression?
$$\log \left( {\frac{8}{{14}}} \right) - $$   $$\log \left( {\frac{{15}}{{16}}} \right) + $$   $$\log \left( {\frac{{35}}{{24}}} \right)$$