Answer
$\{-1\}$.
Work Step by Step
Add $x-9$ to both sides.
$6-x+x-9=2x+9+x-9$
Simplify by combining like terms:
$-3=3x$
Divide both sides by $3$.
$\dfrac{-3}{3}=\dfrac{3x}{3}$
Simplify.
$-1=x$
Hence, the solution to the equation is $\{-1\}$.
