\(\lim\limits_{x\rightarrow-\infty}\left(\sqrt{x^2-3x+2}+x-4\right)=\lim\limits_{x\rightarrow-\infty}\left(\dfrac{-3x+2}{\sqrt{x^2-3x+2}-x}-4\right)\)
\(=\lim\limits_{x\rightarrow-\infty}\left(\dfrac{-3+\dfrac{2}{x}}{-\sqrt{1-\dfrac{3}{x}+\dfrac{2}{x^2}}-1}-4\right)=\dfrac{-3}{-2}-4=-\dfrac{5}{2}\)