#### Answer

$b^y=x$

#### Work Step by Step

RECALL:
$\log_b{x}=y \longrightarrow b^y=x$ where $x, b \gt 0$, and $b\ne 1$.
Use the rule above to convert the given logarithm ti exponential form:
$y=\log_b{x} \longrightarrow b^y=x$
Thus, the missing expression in the given statement is $b^y=x$