Firstly, you need to see what is being asked to do. You need to find a vector equation of a line.Remember that the vector equation of a line is represented as r = a + λb.r is any point on the line, a is a specific point on the line and b is the direction vector of the line.Next, you need to look at the information provided in the question. You have been told that the line 'l' passes through a specific point (1,-1,2). This will be a.You have also been told that the line 'l' will be 'parallel' to the vector (2i + 4k). Therefore, the direction vector of the line 'l' will also be 2i + 4k. Now you have all your information, it can be filled into the equation. l: r = (i -j + 2k) + λ(2i + 4k)You have now finished the question.