Answer
$x=\dfrac{1}{2}$
Work Step by Step
Converting to exponential form, the solution to the given logarithmic equation, $
\log_2{x}=-1
,$ is
\begin{array}{l}\require{cancel}
x=2^{-1}
\\\\
x=\dfrac{1}{2^1}
\\\\
x=\dfrac{1}{2}
.\end{array}