Question 63
$x y z = 1$ applies to real numbers $x$, $y$ and $z$. Calculate the value of the expression
$$
\frac{x+1}{x y + x + 1} + \frac{y+1}{y z + y + 1} + \frac{z+1}{z x + z + 1}
$$
$$
\frac{x+1}{x y + x + 1} + \frac{y+1}{y z + y + 1} + \frac{z+1}{z x + z + 1}
$$