Question

Tính:

\(a.\lim\limits_{x\rightarrow1}\dfrac{x^2-1}{x-1}\)

\(b.\lim\limits_{x\rightarrow-2}\dfrac{x^2-4}{x+2}\)

Answer 1

\(a,\lim\limits_{x\rightarrow1}\dfrac{x^2-1}{x-1}=\)\(\lim\limits_{x\rightarrow1}\dfrac{\left(x-1\right)\left(x+1\right)}{x-1}=\)\(\lim\limits_{x\rightarrow1}\left(x+1\right)=2\)

\(b,\lim\limits_{x\rightarrow-2}\dfrac{x^2-4}{x+2}=\)\(\lim\limits_{x\rightarrow-2}\dfrac{\left(x-2\right)\left(x+2\right)}{x+2}=\)\(\lim\limits_{x\rightarrow-2}\left(x-2\right)=-4\)