Giải thích các bước giải:
$\lim_{x\to 2^-} (\dfrac{1}{x-2}-\dfrac{1}{x^2-4})$
$=\lim_{x\to 2^-} \dfrac{1}{x-2}(1-\dfrac{1}{x+2})$
$=\lim_{x\to 2^-} \dfrac{1}{x-2}.\dfrac{x+2-1}{x+2}$
$=\lim_{x\to 2^-} \dfrac{1}{x-2}.\dfrac{x+1}{x+2}$
$=-\dfrac{1}{2-2}.\dfrac{2+1}{2+2}$
$=-\infty$