The value of   $${(75.8)^2-(55.8)^2\over20}$$

Simplify the following expression.

 25-(4÷2)+11.5+9.5

The least number, by which 1944 must be multiplied so as to make the result a perfect cube is 

Simplify the following equation.
$$ {(100)}^{1\over2}.{(0.001)}^{1\over3}-{(0.0016)}^{1\over4}.{3}^{0}+({5\over4})^{-1} $$

If $${{k^2}\over {k^2-2k+1}}={1\over 6}$$, then what is the value of $${1\over k^3}+k3$$ ?

The value of x in the given equation
$$ {23 ^2 + \sqrt{x}=625}$$

3x² = 36 then what is the value of x?

If $$ a={{\sqrt{3}+\sqrt{2}}\over {\sqrt{3}-\sqrt{2}}}$$ and $$ b={{\sqrt{3}-\sqrt{2}}\over {\sqrt{3}+\sqrt{2}}}$$, then find the value  of $$ {a^2\over b}+{b^2\over a}=?$$