The equation of a line passing through the point on x-axis at a distance of 3 units from the origin and parallel to xy-plane is

The direction cosines of any line parallel to the  xy-plane is  1,1,0and the coordinates of the point which are on  x-axis and at a distance of  3 units from the origin is  3,0,0Therefore, the equation of the line passing through the point  3,0,0and parallel to the line whose direction ratio are1,1,0  is   x−31=y−01=z−00