#### Answer

$\dfrac{\ln{20}}{\ln{9}}$

#### Work Step by Step

Isolate $x$ on the left side by dividing $\ln{9}$ on both sides of the equation to obtain:
$x = \dfrac{\ln{20}}{\ln{9}}$
Thus, the missing expression in the given statement is:
$\dfrac{\ln{20}}{\ln{9}}$