If ${2^x} = {4^y} = {8^z}$ and $xyz = 288,$ then ${1 \over {2x}} + {1 \over {4y}} + {1 \over {8z}} = $
$11/48$
$11/24$
$11/8$
$11/96$
The rationalising factor of ${a^{1/3}} + {a^{ - 1/3}}$ is
If $x + \sqrt {({x^2} + 1)} = a,$ then $x =$
If $x = {2^{1/3}} - {2^{ - 1/3}},$ then $2{x^3} + 6x = $
If ${\left( {{2 \over 3}} \right)^{x + 2}} = {\left( {{3 \over 2}} \right)^{2 - 2x}},$then $x =$
Let ${7 \over {{2^{1/2}} + {2^{1/4}} + 1}}$$ = A + B{.2^{1/4}} + C{.2^{1/2}} + D{.2^{3/4}}$, then $A+B+C+D= . . .$