ok
What i do is initially let "Lamda" = 0 to get your first point on the line
which will be (1,0,2)
Next just choose "Lamda" = 1 to get another point on the line. this other point will now be (0,1,4)
Now the point is (-2,2,7)
So let A = (1,0,2) let B = (-2,2,7)...