\(2\left(x-3\right)^2-2\left(x-3\right)\left(x-4\right)=13-x\)
\(\Leftrightarrow2x^2-12x+18-2\left(x^2-7x+12\right)=13-x\)
\(\Leftrightarrow2x^2-12x+18-2x^2+14x-24=13-x\)
\(\Leftrightarrow2x-6=13-x\)
\(\Leftrightarrow3x=19\Leftrightarrow x=\dfrac{19}{3}\)
Vậy \(x=\dfrac{19}{3}\)