\(\lim\limits_{x\rightarrow2^-}\left(\dfrac{1}{x-2}-\dfrac{1}{\left(x-2\right)\left(x+2\right)}\right)=\lim\limits_{x\rightarrow2^-}\left(\dfrac{x+2-1}{\left(x-2\right)\left(x+2\right)}\right)\)
\(=\lim\limits_{x\rightarrow2^-}\dfrac{-x-1}{\left(2-x\right)\left(x+2\right)}=\dfrac{-3}{0}=-\infty\)