[tex]\huge\text{$n=\boxed{20}$}[/tex]
We need to isolate the variable on one side of the equation.
[tex]\begin{aligned}\frac{n-2}{-3}&=-6&&\smash{\Big|}&&\text{Write an equation.}\\n-2&=18&&\smash{\Big|}&&\text{Multiply both sides by $-3$}\\n&=\boxed{20}&&\smash{\Big|}&&\text{Add $2$ to both sides.}\end{aligned}[/tex]
