Answer
(a) $x=1-\frac{\log 3}{\log 2}$
(b) $x\approx-0.584963$
Work Step by Step
(a) We need to solve:
$2^{1-x}=3 $
We take the log of both sides and use log rules to simplify:
$\log 2^{1-x}=\log 3$
$(1-x)\log 2=\log 3$
$1-x=\frac{\log 3}{\log 2}$
$x=1-\frac{\log 3}{\log 2}$
(b) We use a calculator:
$x\approx-0.584963$