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Câu hỏi: Trong không gian $Oxyz$, cho $C\left( -1;0;2 \right)$ và $D\left( 2;1;-5 \right)$. Phương trình đường thẳng $CD$ là
A. $\dfrac{x-1}{3}=\dfrac{y}{1}=\dfrac{z+2}{-7}.$
B. $\dfrac{x+1}{3}=\dfrac{y}{1}=\dfrac{z-2}{-7}.$
C. $\dfrac{x+1}{1}=\dfrac{y}{1}=\dfrac{z-2}{-3}.$
D. $\dfrac{x-1}{1}=\dfrac{y}{1}=\dfrac{z+2}{-3}.$
A. $\dfrac{x-1}{3}=\dfrac{y}{1}=\dfrac{z+2}{-7}.$
B. $\dfrac{x+1}{3}=\dfrac{y}{1}=\dfrac{z-2}{-7}.$
C. $\dfrac{x+1}{1}=\dfrac{y}{1}=\dfrac{z-2}{-3}.$
D. $\dfrac{x-1}{1}=\dfrac{y}{1}=\dfrac{z+2}{-3}.$
Ta có $\overrightarrow{CD}=\left( 3;1;-7 \right)\Rightarrow $ phương trình đường thẳng $CD:\dfrac{x+1}{3}=\dfrac{y}{1}=\dfrac{z-2}{-7}.$
Đáp án B.