The equation of a line passing through the point 1,1,1and parallel to yz-plane is
x−11=y−10=z−10
x−10=y−11=z−11
x−11=y−01=z−01
x−11=y−00=z−01
The direction cosines of any line parallel to the yz-plane is 0,1,1
Therefore, the equation of the line passing through the point 1,1,1and parallel to the line whose direction ratio are 0,1,1 is x−10=y−11=z−11