If ${a^x} = bc,{b^y} = ca,\,{c^z} = ab,$ then $xyz$=
$0$
$1$
$x + y + z$
$x + y + z + 2$
If $x = \sqrt 7 + \sqrt 3 $ and $xy = 4,$then ${x^4} + {y^4}=$
If ${a^{x - 1}} = bc,{b^{y - 1}} = ca,{c^{z - 1}} = ab,$then $\sum {(1/x) = } $
The value of $\sqrt {[12 - \sqrt {(68 + 48\sqrt 2 )} ]} = $
The equation $\sqrt {(x + 1)} - \sqrt {(x - 1)} = \sqrt {(4x - 1)} $, $x \in R$ has
The value of the fifth root of $10^{10^{10}}$ is