If ${x^{x\root 3 \of x }} = {(x\,.\,\root 3 \of x )^x},$ then $x =$
$64/27$
$-1$
$0$
None of these
The square root of $\sqrt {(50)} + \sqrt {(48)} $ is
${{3\sqrt 2 } \over {\sqrt 6 + \sqrt 3 }} - {{4\sqrt 3 } \over {\sqrt 6 + \sqrt 2 }} + {{\sqrt 6 } \over {\sqrt 3 + \sqrt 2 }} = $
If ${2^x} = {4^y} = {8^z}$ and $xyz = 288,$ then ${1 \over {2x}} + {1 \over {4y}} + {1 \over {8z}} = $
If $x + \sqrt {({x^2} + 1)} = a,$ then $x =$
${{12} \over {3 + \sqrt 5 - 2\sqrt 2 }} = $