#### Answer

$\frac{2}{9}$

#### Work Step by Step

When $x=-\frac{1}{3}$ and $z=\frac{5}{6}$:
$(1-x)(1-x)$
$=[1-(-\frac{1}{3})][1-(\frac{5}{6})]$
$=(1+\frac{1}{3})(1-\frac{5}{6})$
$=(\frac{3}{3}+\frac{1}{3})(\frac{6}{6}-\frac{5}{6})$
$=\frac{4}{3}\times\frac{1}{6}$
$=\frac{2}{3}\times\frac{1}{3}$
$=\frac{2}{9}$