If $$ {3\sqrt{{1-a}\over{a}}}+9={19-3\sqrt{{a}\over{1-a}}}$$, then what is the value of a?

Simplify : $$ {(2x)^{2}-(2y)^{2}-(4x)^{2}}$$

Direction: what should come in place at question mark(?).

$$ {4\over 7}×{2{4\over 5}÷{2\over 5}=?}$$

The value of $$ {\sqrt{0.6912}+{\sqrt{0.5292}}\over {\sqrt{0.6912}-{\sqrt{0.5292}}}}$$ is:

Evaluate: $$ {9।3-5।-5।-5।4।÷10\over-3(5)-2×4÷2}$$

3x² = 36 then what is the value of x?

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

If  $$\sqrt{2}=1.414$$, the value of $${ \sqrt{2}-1\over\sqrt{2}+1}$$  is nearest to