Ngân hàng bài tập
B
Tính giới hạn \(\lim\limits_{x\to-3}\left|\dfrac{-x^2-x+6}{x^2+3x}\right|\).
 | \(\dfrac{1}{3}\) |
 | \(\dfrac{2}{3}\) |
 | \(\dfrac{5}{3}\) |
 | \(\dfrac{3}{5}\) |
1 lời giải
Chọn phương án C.
\(\begin{aligned}
\lim\limits_{x\to-3}\left|\dfrac{-x^2-x+6}{x^2+3x}\right|&=\lim\limits_{x\to-3}\left|\dfrac{-(x-2)(x+3)}{x(x+3)}\right|\\
&=\lim\limits_{x\to-3}\left|\dfrac{-(x-2)}{x}\right|\\
&=\left|\dfrac{-(-3-2)}{-3}\right|=\dfrac{5}{3}.
\end{aligned}\)