Answer
$ - 0.37$
Work Step by Step
$\log_{b}(\sqrt x \sqrt y) /z$
$=\log_{b}\sqrt x \sqrt y - \log_{b}z $
$=0.5\log_{b}xy - \log_{b}z$
$=0.5(\log_{b}x+log_{b}y) - \log_{b}z$
$ = 0.5(0.36+0.56) - 0.83$
$ = .18+0.28 - 0.83$
$ =0.46 - 0.83$
$ = - 0.37$