Điểm nào sau đây thuộc đường thẳng \(d:\left\{ \begin{array}{l} x = 1 + 2t\\ y = 3 - t \end{array} \right.?\)

* Hướng dẫn giải

\(M\left( {2;-1} \right) \Rightarrow \left\{ \begin{array}{l} 2 = 1 + 2t\\ - 1 = 3 - t \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} t = \frac{1}{2}\\ t = 4 \end{array} \right.\,\,\left( {VN} \right) \to M\not \in d.\)

\(N\left( {-7;0} \right) \Rightarrow \left\{ \begin{array}{l} - 7 = 1 + 2t\\ 0 = 3 - t \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} t = - 4\\ t = 3 \end{array} \right.\,\left( {VN} \right) \to N\not \in d.\)

\([P\left( {3;5} \right) \Rightarrow \left\{ \begin{array}{l} 3 = 1 + 2t\\ 5 = 3 - t \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} t = 1\\ t = - 2 \end{array} \right.\,\left( {VN} \right) \to P\not \in d.\)

\(Q\left( {3;{\rm{ }}2} \right) \Rightarrow \left\{ \begin{array}{l} 3 = 1 + 2t\\ 2 = 3 - t \end{array} \right. \Leftrightarrow t = 1 \to Q \in d.\)