#### Answer

$n=-9$

#### Work Step by Step

We are trying to solve for the given variable so that the proportion is true.
To determine if a proportion is true, we have to find if the cross products are equal.
The cross products of $\frac{a}{b}=\frac{c}{d}$ are $a \cdot d$ and $b \cdot c$.
$-18*n=3*54$
$-18n=162$
$-18n\div-18=162\div-18$
$n=-9$