Câu 5:
\(\lim\limits_{x\rightarrow3}\dfrac{x^2-9}{x-3}=\lim\limits_{x\rightarrow3}\dfrac{\left(x-3\right)\left(x+3\right)}{x-3}=\lim\limits_{x\rightarrow3}\left(x+3\right)=6\)
Câu 6:
\(\lim\limits_{x\rightarrow+\infty}\dfrac{2x-5}{3x+4}=\lim\limits_{x\rightarrow+\infty}\dfrac{2-\dfrac{5}{x}}{3+\dfrac{4}{x}}=\dfrac{2}{3}\)