If ${\left( {{2 \over 3}} \right)^{x + 2}} = {\left( {{3 \over 2}} \right)^{2 - 2x}},$then $x =$
$1$
$3$
$4$
$0$
Solution of the equation $\sqrt {(x + 10)} + \sqrt {(x - 2)} = 6$ are
The value of ${{15} \over {\sqrt {10} + \sqrt {20} + \sqrt {40} - \sqrt 5 - \sqrt {80} }}$ is
The rationalising factor of $2\sqrt 3 - \sqrt 7 $ is
The rationalising factor of ${a^{1/3}} + {a^{ - 1/3}}$ is
If ${a^x} = bc,{b^y} = ca,\,{c^z} = ab,$ then $xyz$=